Tautologies and other forms of circular reasoning.

[Nick Thompson]

Arlo, Glen, and Frank,

I would like us to come to some sort of common understanding of how to use
the word, tautology, because I think the definitional issue is keeping us
from making progress on more substantive matters.

See how much of the following you both can agree with:

(1)   We are talking here about a broad class of reasoning called circular,
wherein the conclusion is at least partly determined, not by any facts about
the world, but by information stated in the question.  

(2) A tautology is the most narrowly defined example of such reasoning.  In
tautology, we already know the answer when the question has been asked.   No
doubts can be raised.  This meaning can be further limited to certain kinds
of mathematical expressions.  

(3) In circular reasoning, (a) the conclusion can  be -- at least partly --
worked out from the question because the conclusion contains the question
embedded in it but (b) it is not entirely circular, because it also contains
other material that is not contained in the question.  So, for instance, if
the question, "What selection pressure made polar bears white?" the answer
"a selection pressure that made polar bears white"  is entirely circular.
It is a simple repetition of the question as an assertion.  But notice that
the answer , "A selection for white fur", while highly circular, is not
entirely so because it rules out the possibility that the selection was for
some correlated trait -- conservation of melanin, say.  That information is
not entailed in the question.

(4) Without trying to settle the question of how many forms of semi-circular
reasoning there might be, Lipton and Thompson described a class of
semi-circular reasoning called "recursive".  (The idea in the name was that
the conclusion of the reasoning "runs back" to the question for some of its
information.  Thus, this part of the explanation is uninformative.)  In
recursive reasoning, the uninformative part of the explanation is held
within a frame that is itself informative.  If the question is, "Why is the
oil in my car clean?", then the answer, "Because it went through a clean oil
filter" is not completely circular but recursive, because the frame, "went
through _____ filter" it rules out the possibility that the oil is clean
simply because it has not yet been through the engine. The polar bear
explanation above is another example of a recursive explanation.  "His AIDS
symptoms are caused by the AIDS virus" is another.  We thought that these
recursive explanations play an important role in the development of
scientific explanations, because they guided scientists as they collected
data that served to revise the frame while keeping the goal of the
explanation clearly in view.  

4.  Now where I am confused is about the relationship between completely
circular reasoning and tautological reasoning.  The example given at the
dictionary of philosophy of a tautology is "Both Paul and Mary were at the
meeting; therefore Paul was at the meeting."  If this is the type-case of a
tautological explanation, then I cannot see why "A selection pressure that
made polar bears white" is not another example, given the question, "What
selection pressure made polar bears white?"    

I think at least two of you can help me see where I am going wrong. I think
you are going to tell me that I have mixed apples and oranges above, by
talking indiscriminately about questions and answers and arguments and
conclusions.  Can you straighten me out on that?   Can you specify the usage
community for which your proposed usage is current?  Given the FRIAM group,
can you suggest a usage convention you would recommend for our further
conversation about plurality in scientific explanation?

Thanks,

Nick

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of glen
Sent: Friday, April 12, 2013 12:39 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] pluralism in science

Arlo Barnes wrote at 04/12/2013 11:21 AM:
> I thought the tautology is that scientists are trying to converge on
> Truth, but Truth is defined as what scientists converge on.

I don't think that's (technically) tautology.  I've understood that as
"begging the question" or assuming your conclusion.  It's related to
tautology, but weaker, allowing other stuff to participate in the inference
process.  Tautology is straight equality.  Petitio principii can have side
effects and other conclusions, of which only one conclusion is equivalent to
one assumption.

> I would break the cycle by arguing that scientists are not trying to
> converge on anything, at least not if they are doing it right. They
> would expect that minus experimental error and statistical variation
> the results of their experiments would reflect some single coherent
> model of reality, even one that we currently have no conception of,
> but they are not supposed to and possibly can't assume such.

Agreed!  ... not if they're doing it right.  The trick is how do we know
who's doing it right?

--
=><= glen e. p. ropella
Cause every supersonic jerkoff who plugs into the game


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[Nick Thompson]

Ah.  Thanks glen.  This is super helpful.  Larding below.

 

-----Original Message-----
From: glen [mailto:[hidden email]]
Sent: Friday, April 12, 2013 4:01 PM
To: Nicholas Thompson
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Nicholas Thompson wrote at 04/12/2013 02:18 PM:

> See how much of the following you both can agree with:

>

> (1)   We are talking here about a broad class of reasoning called circular,

> wherein the conclusion is at least partly determined, not by any facts

> about the world, but by information stated in the question.

 

I agree completely with this.

 

[NST ==>Lets put that in the bank <==NST]

 

> (2) A tautology is the most narrowly defined example of such reasoning.  In

> tautology, we already know the answer when the question has been asked.   No

> doubts can be raised.  This meaning can be further limited to certain

> kinds of mathematical expressions.

 

I agree mostly with this.  The only exception is complicated deduction, where many premises tortuously, mechanically, crank through to "theorems" that aren't obvious in how they map back to the premises.

There are some people who believe this kind of "computational" deduction is more than mere tautology.  There are some who reduce it to mere tautology.

[NST ==>There seem to be two issues here.  (1) Whether the conclusion is entailed in the premise (or the answer in the question or (2) whether the entailed answer can be anticipated.   That a white T-shirt confirms that All Ravens are Black is entailed by logic but totally unanticipated by me, and, indeed, I still don’t get it.  Am I correct that you want to exclude for “tautological” sequences of reasoning where the conclusion is entailed the premises (or the answer in the question) but the path is so complex that we cannot anticipate it?  <==NST]

 

> (3) In circular reasoning, (a) the conclusion can  be -- at least

> partly -- worked out from the question because the conclusion contains

> the question embedded in it but (b) it is not entirely circular,

> because it also contains other material that is not contained in the

> question.  So, for instance, if the question, "What selection pressure

> made polar bears white?" the answer "a selection pressure that made polar bears white"  is entirely circular.

> It is a simple repetition of the question as an assertion.  But notice

> that the answer , "A selection for white fur", while highly circular,

> is not entirely so because it rules out the possibility that the

> selection was for some correlated trait -- conservation of melanin,

> say.  That information is not entailed in the question.

 

I don't disagree or agree, here.  I think this equivocates on "information" or "material not contained in the question".  The only way to avoid this is to formalize the definition so that everything within the circular part and the non-circular part can be unambiguously identified.

[NST ==>I see what you mean.  By using this language I introduce ambiguity that really shouldn’t perhaps enter a conversation about logic.  Still, the make the conversation relevant, I am tempted from rigor. <==NST]

 

> (4) Without trying to settle the question of how many forms of

> semi-circular reasoning there might be, Lipton and Thompson described

> a class of semi-circular reasoning called "recursive".  (The idea in

> the name was that the conclusion of the reasoning "runs back" to the

> question for some of its information.  Thus, this part of the

> explanation is uninformative.)  In recursive reasoning, the

> uninformative part of the explanation is held within a frame that is

> itself informative.  If the question is, "Why is the oil in my car

> clean?", then the answer, "Because it went through a clean oil filter"

> is not completely circular but recursive, because the frame, "went

> through _____ filter" it rules out the possibility that the oil is

> clean simply because it has not yet been through the engine. The polar

> bear explanation above is another example of a recursive explanation. 

> "His AIDS symptoms are caused by the AIDS virus" is another.  We

> thought that these recursive explanations play an important role in

> the development of scientific explanations, because they guided

> scientists as they collected data that served to revise the frame while keeping the goal of the explanation clearly in view.

 

I agree that there are some of these filter explanations that are recursive.  But some of them are not.  And the more useful filter explanations are not actually recursive, but merely iterative.

[NST ==>The first time you made this distinction, I couldn’t quite get it.  Can you say a bit more?  It wold seem to me that recursion could happen only once, but that iteration would require several instances.  So I can imagine an interation of recursions but not the reverse.  In short, I don’t know how talk this talk, yet.  <==NST]

 

> 4.  Now where I am confused is about the relationship between

> completely circular reasoning and tautological reasoning.  The example

> given at the dictionary of philosophy of a tautology is "Both Paul and

> Mary were at the meeting; therefore Paul was at the meeting."  If this

> is the type-case of a tautological explanation, then I cannot see why

> "A selection pressure that made polar bears white" is not another

> example, given the question, "What selection pressure made polar bears white?"

 

I disagree with your dictionary. I think of a tautology as "saying the exact same thing with different words", not saying a partly similar thing with different words.  It's an if-and-only-if, not merely an if.

 

"P ^ M -> P" leaves out information.  So, saying "P" is not the same as saying "P^M".[NST ==>AHHHHH!  So total entailment is not sufficient to tautology, on your account.  I have to think about that.  So all white swans are white is a tautology but (1) All swans are white (2) this bird is a swan (3) this bird is white is not.  <==NST]   

 

But, as I said above, there are some people who claim that all deduction is tautology.  They would probably identify different types of tautology (e.g. simple or minimal) versus a complicated (perhaps irreversible) deduction.

[NST ==>OK.  We are on the same page.  So what term do you want to use? <==NST]

 

> I think at least two of you can help me see where I am going wrong. I

> think you are going to tell me that I have mixed apples and oranges

> above, by talking indiscriminately about questions and answers and arguments and

> conclusions.  Can you straighten me out on that?   Can you specify the usage

> community for which your proposed usage is current?  Given the FRIAM

> group, can you suggest a usage convention you would recommend for our

> further conversation about plurality in scientific explanation?

 

I can't straighten anyone out. ;-)  But my suggestion would be that tautology be used for the most direct, reversible, synonymous

statements: "polar bears are white because polar bears are white".  And anything more sophisticated should be given another name.[NST ==>how about long and short tautologies?  Probably too whimsical.  OK.  How about …. Tautologies for the narrow case, and analytical conclusions for the deductions.  <==NST]   

 

--

=><= glen e. p. ropella

Oh man this egg is way too hot

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[glen ropella]

Nicholas Thompson wrote at 04/12/2013 03:51 PM:
> [NST ==>[...] Am I correct that you want to exclude for
> "tautological" sequences of reasoning where the conclusion is entailed the
> premises (or the answer in the question) but the path is so complex that we
> cannot anticipate it?  <==NST]

Yes.  On my more flippant days, I'll point out that some people claim
unanticipatable, complicated deduction reduces to tautology.  And I may
say it when I get frustrated at people who don't understand the
difference between deduction and induction.

But for the most part, yes.  A purely deductive system that can hit upon
true, but surprising, theorems, is not merely tautology.

> [NST ==>The first time you made this distinction, I couldn't quite get it.
> Can you say a bit more?  It wold seem to me that recursion could happen only
> once, but that iteration would require several instances.  So I can imagine
> an interation of recursions but not the reverse.  In short, I don't know how
> talk this talk, yet.  <==NST]

Both recursion and iteration can be infinite.  The difference lies the
focus of the repetition. Recursion puts more focus on the I/O of the
process, what comes out of any given application must make sense going
in.  The input and output must be commensurate.

Iteration puts more focus on the procedure, in particular the state, the
conditions that obtain.  As long as the conditions still tolerate it,
the iteration will continue, regardless of whether the I/O is
meaningful.  Iteration can wander more than recursion.  Recursion is
less prone to the adage "garbage in => garbage out".  So, in your filter
metaphor, if your filter stays the same, each time the fluid is pushed
through, it will filter more of the same particles out of the fluid
until there are none left (or the filter fills up).  With iteration,
your filter might change each time it's used because of unforeseen
effects.  For example, if your filter is supposed to extract particles
1-100 millimeters, but you use it so much that it starts to develop
densely packed regions, then it may begin to filter only particles that
are 1-100 nanometers.

The filter is a hysterical process.  It has memory.  If you replace the
filter with a new one each time the fluid goes through it, then you've
got recursion.  If you allow the filter to get progressively dirty, then
you've got iteration.  Iteration is most aligned with stateful
repetition.  Recursion is most aligned with stateless repetition.

> "P ^ M -> P" leaves out information.  So, saying "P" is not the same as
> saying "P^M".[NST ==>AHHHHH!  So total entailment is not sufficient to
> tautology, on your account.  I have to think about that.  So all white swans
> are white is a tautology but (1) All swans are white (2) this bird is a swan
> (3) this bird is white is not.  <==NST]

Not technically, no.  But if pressed, I would consider the context of
the accusation.  When I'm talking to someone like you, who might
actually listen to me, I'd say "no".  When talking to someone who just
likes to hear themselves talk, I'd say "ok, sure, 1) all swans are white
plus 2) this is a swan, therefore 3) this swan is white is close enough
to a tautology for me to call it that for this conversation."

But when/if I allow that, I'm on a slippery slope to calling all
deduction tautological.

> But, as I said above, there are some people who claim that all deduction is
> tautology.  They would probably identify different types of tautology (e.g.
> simple or minimal) versus a complicated (perhaps irreversible) deduction.
>
> [NST ==>OK.  We are on the same page.  So what term do you want to use?
> <==NST]

I see no problem with "deduction" or perhaps "inference", "grammatical
transformation", etc.  Heck, I'd even be ok with "simulation",
"numerical analysis", "play it forward", "let it roll", and "Deism".

> [NST ==>how about
> long and short tautologies?  Probably too whimsical.  OK.  How about ..
> Tautologies for the narrow case, and analytical conclusions for the
> deductions.  <==NST]  

I like "analytical conclusions" as a synonym for "complicated
deduction".  The only issue is the teleological sense I get from
"conclusion", I suppose.  How about "analytical end state"? ;-)

--
=><= glen e. p. ropella
Lobsterbacks attack the town again


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[Nick Thompson]

I have a terrible time with the word "state";  how about analytical output?


Otherwise we're good.  

Nick

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of glen
Sent: Friday, April 12, 2013 5:40 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

Nicholas Thompson wrote at 04/12/2013 03:51 PM:
> [NST ==>[...] Am I correct that you want to exclude for "tautological"
> sequences of reasoning where the conclusion is entailed the premises
> (or the answer in the question) but the path is so complex that we
> cannot anticipate it?  <==NST]

Yes.  On my more flippant days, I'll point out that some people claim
unanticipatable, complicated deduction reduces to tautology.  And I may say
it when I get frustrated at people who don't understand the difference
between deduction and induction.

But for the most part, yes.  A purely deductive system that can hit upon
true, but surprising, theorems, is not merely tautology.

> [NST ==>The first time you made this distinction, I couldn't quite get it.
> Can you say a bit more?  It wold seem to me that recursion could
> happen only once, but that iteration would require several instances.  
> So I can imagine an interation of recursions but not the reverse.  In
> short, I don't know how talk this talk, yet.  <==NST]

Both recursion and iteration can be infinite.  The difference lies the focus
of the repetition. Recursion puts more focus on the I/O of the process, what
comes out of any given application must make sense going in.  The input and
output must be commensurate.

Iteration puts more focus on the procedure, in particular the state, the
conditions that obtain.  As long as the conditions still tolerate it, the
iteration will continue, regardless of whether the I/O is meaningful.
Iteration can wander more than recursion.  Recursion is less prone to the
adage "garbage in => garbage out".  So, in your filter metaphor, if your
filter stays the same, each time the fluid is pushed through, it will filter
more of the same particles out of the fluid until there are none left (or
the filter fills up).  With iteration, your filter might change each time
it's used because of unforeseen effects.  For example, if your filter is
supposed to extract particles
1-100 millimeters, but you use it so much that it starts to develop densely
packed regions, then it may begin to filter only particles that are 1-100
nanometers.

The filter is a hysterical process.  It has memory.  If you replace the
filter with a new one each time the fluid goes through it, then you've got
recursion.  If you allow the filter to get progressively dirty, then you've
got iteration.  Iteration is most aligned with stateful repetition.
Recursion is most aligned with stateless repetition.

> "P ^ M -> P" leaves out information.  So, saying "P" is not the same
> as saying "P^M".[NST ==>AHHHHH!  So total entailment is not sufficient
> to tautology, on your account.  I have to think about that.  So all
> white swans are white is a tautology but (1) All swans are white (2)
> this bird is a swan
> (3) this bird is white is not.  <==NST]

Not technically, no.  But if pressed, I would consider the context of the
accusation.  When I'm talking to someone like you, who might actually listen
to me, I'd say "no".  When talking to someone who just likes to hear
themselves talk, I'd say "ok, sure, 1) all swans are white plus 2) this is a
swan, therefore 3) this swan is white is close enough to a tautology for me
to call it that for this conversation."

But when/if I allow that, I'm on a slippery slope to calling all deduction
tautological.

> But, as I said above, there are some people who claim that all
> deduction is tautology.  They would probably identify different types of
tautology (e.g.
> simple or minimal) versus a complicated (perhaps irreversible) deduction.
>
> [NST ==>OK.  We are on the same page.  So what term do you want to use?
> <==NST]

I see no problem with "deduction" or perhaps "inference", "grammatical
transformation", etc.  Heck, I'd even be ok with "simulation", "numerical
analysis", "play it forward", "let it roll", and "Deism".

> [NST ==>how about
> long and short tautologies?  Probably too whimsical.  OK.  How about ..
> Tautologies for the narrow case, and analytical conclusions for the
> deductions.  <==NST]  

I like "analytical conclusions" as a synonym for "complicated deduction".
The only issue is the teleological sense I get from "conclusion", I suppose.
How about "analytical end state"? ;-)

--
=><= glen e. p. ropella
Lobsterbacks attack the town again


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[Douglas Roberts-2]

Oh shit. Nick's in a state again.

On Apr 12, 2013 9:23 PM, "Nicholas Thompson" <[hidden email]> wrote:

I have a terrible time with the word "state";  how about analytical output?


Otherwise we're good.

Nick

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of glen
Sent: Friday, April 12, 2013 5:40 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

Nicholas Thompson wrote at 04/12/2013 03:51 PM:
> [NST ==>[...] Am I correct that you want to exclude for "tautological"
> sequences of reasoning where the conclusion is entailed the premises
> (or the answer in the question) but the path is so complex that we
> cannot anticipate it?  <==NST]

Yes.  On my more flippant days, I'll point out that some people claim
unanticipatable, complicated deduction reduces to tautology.  And I may say
it when I get frustrated at people who don't understand the difference
between deduction and induction.

But for the most part, yes.  A purely deductive system that can hit upon
true, but surprising, theorems, is not merely tautology.

> [NST ==>The first time you made this distinction, I couldn't quite get it.
> Can you say a bit more?  It wold seem to me that recursion could
> happen only once, but that iteration would require several instances.
> So I can imagine an interation of recursions but not the reverse.  In
> short, I don't know how talk this talk, yet.  <==NST]

Both recursion and iteration can be infinite.  The difference lies the focus
of the repetition. Recursion puts more focus on the I/O of the process, what
comes out of any given application must make sense going in.  The input and
output must be commensurate.

Iteration puts more focus on the procedure, in particular the state, the
conditions that obtain.  As long as the conditions still tolerate it, the
iteration will continue, regardless of whether the I/O is meaningful.
Iteration can wander more than recursion.  Recursion is less prone to the
adage "garbage in => garbage out".  So, in your filter metaphor, if your
filter stays the same, each time the fluid is pushed through, it will filter
more of the same particles out of the fluid until there are none left (or
the filter fills up).  With iteration, your filter might change each time
it's used because of unforeseen effects.  For example, if your filter is
supposed to extract particles
1-100 millimeters, but you use it so much that it starts to develop densely
packed regions, then it may begin to filter only particles that are 1-100
nanometers.

The filter is a hysterical process.  It has memory.  If you replace the
filter with a new one each time the fluid goes through it, then you've got
recursion.  If you allow the filter to get progressively dirty, then you've
got iteration.  Iteration is most aligned with stateful repetition.
Recursion is most aligned with stateless repetition.

> "P ^ M -> P" leaves out information.  So, saying "P" is not the same
> as saying "P^M".[NST ==>AHHHHH!  So total entailment is not sufficient
> to tautology, on your account.  I have to think about that.  So all
> white swans are white is a tautology but (1) All swans are white (2)
> this bird is a swan
> (3) this bird is white is not.  <==NST]

Not technically, no.  But if pressed, I would consider the context of the
accusation.  When I'm talking to someone like you, who might actually listen
to me, I'd say "no".  When talking to someone who just likes to hear
themselves talk, I'd say "ok, sure, 1) all swans are white plus 2) this is a
swan, therefore 3) this swan is white is close enough to a tautology for me
to call it that for this conversation."

But when/if I allow that, I'm on a slippery slope to calling all deduction
tautological.

> But, as I said above, there are some people who claim that all
> deduction is tautology.  They would probably identify different types of
tautology (e.g.
> simple or minimal) versus a complicated (perhaps irreversible) deduction.
>
> [NST ==>OK.  We are on the same page.  So what term do you want to use?
> <==NST]

I see no problem with "deduction" or perhaps "inference", "grammatical
transformation", etc.  Heck, I'd even be ok with "simulation", "numerical
analysis", "play it forward", "let it roll", and "Deism".

> [NST ==>how about
> long and short tautologies?  Probably too whimsical.  OK.  How about ..
> Tautologies for the narrow case, and analytical conclusions for the
> deductions.  <==NST]

I like "analytical conclusions" as a synonym for "complicated deduction".
The only issue is the teleological sense I get from "conclusion", I suppose.
How about "analytical end state"? ;-)

--
=><= glen e. p. ropella
Lobsterbacks attack the town again


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Meets Fridays 9a-11:30 at cafe at St. John's College
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[Nick Thompson]

D

Does saying that a thing is in a state mean anything more than that you have tried to measure  something about that thing and that your measurement theory gives you confidence that you have been successful?  Or, perhaps, the switches on some box are set to some position or other.  And while I am asking dumb questions, to hard scientists (as opposed to biologists), does the word system mean anything more than whatever tf we happen to be talking about at the moment?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Friday, April 12, 2013 9:25 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Oh shit. Nick's in a state again.

On Apr 12, 2013 9:23 PM, "Nicholas Thompson" <[hidden email]> wrote:

I have a terrible time with the word "state";  how about analytical output?


Otherwise we're good.

Nick

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of glen
Sent: Friday, April 12, 2013 5:40 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

Nicholas Thompson wrote at 04/12/2013 03:51 PM:
> [NST ==>[...] Am I correct that you want to exclude for "tautological"
> sequences of reasoning where the conclusion is entailed the premises
> (or the answer in the question) but the path is so complex that we
> cannot anticipate it?  <==NST]

Yes.  On my more flippant days, I'll point out that some people claim
unanticipatable, complicated deduction reduces to tautology.  And I may say
it when I get frustrated at people who don't understand the difference
between deduction and induction.

But for the most part, yes.  A purely deductive system that can hit upon
true, but surprising, theorems, is not merely tautology.

> [NST ==>The first time you made this distinction, I couldn't quite get it.
> Can you say a bit more?  It wold seem to me that recursion could
> happen only once, but that iteration would require several instances.
> So I can imagine an interation of recursions but not the reverse.  In
> short, I don't know how talk this talk, yet.  <==NST]

Both recursion and iteration can be infinite.  The difference lies the focus
of the repetition. Recursion puts more focus on the I/O of the process, what
comes out of any given application must make sense going in.  The input and
output must be commensurate.

Iteration puts more focus on the procedure, in particular the state, the
conditions that obtain.  As long as the conditions still tolerate it, the
iteration will continue, regardless of whether the I/O is meaningful.
Iteration can wander more than recursion.  Recursion is less prone to the
adage "garbage in => garbage out".  So, in your filter metaphor, if your
filter stays the same, each time the fluid is pushed through, it will filter
more of the same particles out of the fluid until there are none left (or
the filter fills up).  With iteration, your filter might change each time
it's used because of unforeseen effects.  For example, if your filter is
supposed to extract particles
1-100 millimeters, but you use it so much that it starts to develop densely
packed regions, then it may begin to filter only particles that are 1-100
nanometers.

The filter is a hysterical process.  It has memory.  If you replace the
filter with a new one each time the fluid goes through it, then you've got
recursion.  If you allow the filter to get progressively dirty, then you've
got iteration.  Iteration is most aligned with stateful repetition.
Recursion is most aligned with stateless repetition.

> "P ^ M -> P" leaves out information.  So, saying "P" is not the same
> as saying "P^M".[NST ==>AHHHHH!  So total entailment is not sufficient
> to tautology, on your account.  I have to think about that.  So all
> white swans are white is a tautology but (1) All swans are white (2)
> this bird is a swan
> (3) this bird is white is not.  <==NST]

Not technically, no.  But if pressed, I would consider the context of the
accusation.  When I'm talking to someone like you, who might actually listen
to me, I'd say "no".  When talking to someone who just likes to hear
themselves talk, I'd say "ok, sure, 1) all swans are white plus 2) this is a
swan, therefore 3) this swan is white is close enough to a tautology for me
to call it that for this conversation."

But when/if I allow that, I'm on a slippery slope to calling all deduction
tautological.

> But, as I said above, there are some people who claim that all
> deduction is tautology.  They would probably identify different types of
tautology (e.g.
> simple or minimal) versus a complicated (perhaps irreversible) deduction.
>
> [NST ==>OK.  We are on the same page.  So what term do you want to use?
> <==NST]

I see no problem with "deduction" or perhaps "inference", "grammatical
transformation", etc.  Heck, I'd even be ok with "simulation", "numerical
analysis", "play it forward", "let it roll", and "Deism".

> [NST ==>how about
> long and short tautologies?  Probably too whimsical.  OK.  How about ..
> Tautologies for the narrow case, and analytical conclusions for the
> deductions.  <==NST]

I like "analytical conclusions" as a synonym for "complicated deduction".
The only issue is the teleological sense I get from "conclusion", I suppose.
How about "analytical end state"? ;-)

--
=><= glen e. p. ropella
Lobsterbacks attack the town again


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[Douglas Roberts-2]

Nick,

I spent a considerable amount of time thinking about this between sips of coffee this morning.

--Doug

On Sat, Apr 13, 2013 at 12:19 AM, Nicholas Thompson <[hidden email]> wrote:

D

Does saying that a thing is in a state mean anything more than that you have tried to measure  something about that thing and that your measurement theory gives you confidence that you have been successful?  Or, perhaps, the switches on some box are set to some position or other.  And while I am asking dumb questions, to hard scientists (as opposed to biologists), does the word system mean anything more than whatever tf we happen to be talking about at the moment?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Friday, April 12, 2013 9:25 PM

To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Oh shit. Nick's in a state again.

On Apr 12, 2013 9:23 PM, "Nicholas Thompson" <[hidden email]> wrote:

I have a terrible time with the word "state";  how about analytical output?


Otherwise we're good.

Nick

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of glen
Sent: Friday, April 12, 2013 5:40 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

Nicholas Thompson wrote at 04/12/2013 03:51 PM:
> [NST ==>[...] Am I correct that you want to exclude for "tautological"
> sequences of reasoning where the conclusion is entailed the premises
> (or the answer in the question) but the path is so complex that we
> cannot anticipate it?  <==NST]

Yes.  On my more flippant days, I'll point out that some people claim
unanticipatable, complicated deduction reduces to tautology.  And I may say
it when I get frustrated at people who don't understand the difference
between deduction and induction.

But for the most part, yes.  A purely deductive system that can hit upon
true, but surprising, theorems, is not merely tautology.

> [NST ==>The first time you made this distinction, I couldn't quite get it.
> Can you say a bit more?  It wold seem to me that recursion could
> happen only once, but that iteration would require several instances.
> So I can imagine an interation of recursions but not the reverse.  In
> short, I don't know how talk this talk, yet.  <==NST]

Both recursion and iteration can be infinite.  The difference lies the focus
of the repetition. Recursion puts more focus on the I/O of the process, what
comes out of any given application must make sense going in.  The input and
output must be commensurate.

Iteration puts more focus on the procedure, in particular the state, the
conditions that obtain.  As long as the conditions still tolerate it, the
iteration will continue, regardless of whether the I/O is meaningful.
Iteration can wander more than recursion.  Recursion is less prone to the
adage "garbage in => garbage out".  So, in your filter metaphor, if your
filter stays the same, each time the fluid is pushed through, it will filter
more of the same particles out of the fluid until there are none left (or
the filter fills up).  With iteration, your filter might change each time
it's used because of unforeseen effects.  For example, if your filter is
supposed to extract particles
1-100 millimeters, but you use it so much that it starts to develop densely
packed regions, then it may begin to filter only particles that are 1-100
nanometers.

The filter is a hysterical process.  It has memory.  If you replace the
filter with a new one each time the fluid goes through it, then you've got
recursion.  If you allow the filter to get progressively dirty, then you've
got iteration.  Iteration is most aligned with stateful repetition.
Recursion is most aligned with stateless repetition.

> "P ^ M -> P" leaves out information.  So, saying "P" is not the same
> as saying "P^M".[NST ==>AHHHHH!  So total entailment is not sufficient
> to tautology, on your account.  I have to think about that.  So all
> white swans are white is a tautology but (1) All swans are white (2)
> this bird is a swan
> (3) this bird is white is not.  <==NST]

Not technically, no.  But if pressed, I would consider the context of the
accusation.  When I'm talking to someone like you, who might actually listen
to me, I'd say "no".  When talking to someone who just likes to hear
themselves talk, I'd say "ok, sure, 1) all swans are white plus 2) this is a
swan, therefore 3) this swan is white is close enough to a tautology for me
to call it that for this conversation."

But when/if I allow that, I'm on a slippery slope to calling all deduction
tautological.

> But, as I said above, there are some people who claim that all
> deduction is tautology.  They would probably identify different types of
tautology (e.g.
> simple or minimal) versus a complicated (perhaps irreversible) deduction.
>
> [NST ==>OK.  We are on the same page.  So what term do you want to use?
> <==NST]

I see no problem with "deduction" or perhaps "inference", "grammatical
transformation", etc.  Heck, I'd even be ok with "simulation", "numerical
analysis", "play it forward", "let it roll", and "Deism".

> [NST ==>how about
> long and short tautologies?  Probably too whimsical.  OK.  How about ..
> Tautologies for the narrow case, and analytical conclusions for the
> deductions.  <==NST]

I like "analytical conclusions" as a synonym for "complicated deduction".
The only issue is the teleological sense I get from "conclusion", I suppose.
How about "analytical end state"? ;-)

--
=><= glen e. p. ropella
Lobsterbacks attack the town again


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--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

505-455-7333 - Office
505-672-8213 - Mobile

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[glen ep ropella]

"Output" not a good word for that at all. We can go back to conclusion, in the sense of "the transformation has stopped". I'm OK with that.

Nicholas  Thompson <[hidden email]> wrote:

>I have a terrible time with the word "state";  how about analytical
>output?
>
>
>Otherwise we're good.  
>
>Nick

--
glen ep ropella 971-255-2847

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[Marcus G. Daniels]

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5))
$ ghc --make foo.hs
$ ./foo
([6,7,8,9,10],11)

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[Nick Thompson]

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

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[Marcus G. Daniels]

On 4/13/13 2:05 PM, Nicholas Thompson wrote:
> Can anybody translate this for a non programmer person?
>
A state may be a complex graph, or a high dimensional space, but it is
still useful to recognize it can be represented by a value and that
(formal) transformations can be made either as a whole or in parts.  
Since a change to a part is a change to the whole, not being clear on
how the composition works is bad.   Functional programming (roughly
speaking,  recursion) requires this consistency.  It's not that
iteration is a more versatile description, but it is sloppier.   Nothing
gets glossed-over using monadic types for state.  In the example code,
e.g., the counter state cannot escape or be mutated outside the scope of
the `runState'.

Marcus

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[Douglas Roberts-2]

Nick,

I surprised that you are not more conversant  in computer languages.  You're always, well, niggling about the meaning of this word, or that one in the context of this or that conversation.

With computer languages, there are very few ambiguities, contextual or other wise. Kind of like mathematics. For one as worried as you often appear to be about the true meaning of the written word, I would have thought that you would positively revel at the ability to express yourself with nearly absolute crystal clarity, no ambiguities whatsoever.

Could it be that you seek out the ambiguities that are ever present  in human languages to give yourself something to pounce upon and worry over, and to provide the opportunity to engage in nearly endless conversations?

--Doug

On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson <[hidden email]> wrote:

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

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--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

505-455-7333 - Office
505-672-8213 - Mobile

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[Nick Thompson]

Could be!

 

Ok.  Now that that is behind us, what did the message mean?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Saturday, April 13, 2013 3:02 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Nick,

 

I surprised that you are not more conversant  in computer languages.  You're always, well, niggling about the meaning of this word, or that one in the context of this or that conversation.

 

With computer languages, there are very few ambiguities, contextual or other wise. Kind of like mathematics. For one as worried as you often appear to be about the true meaning of the written word, I would have thought that you would positively revel at the ability to express yourself with nearly absolute crystal clarity, no ambiguities whatsoever.

 

Could it be that you seek out the ambiguities that are ever present  in human languages to give yourself something to pounce upon and worry over, and to provide the opportunity to engage in nearly endless conversations?

 

--Doug

On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson <[hidden email]> wrote:

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

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--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

505-455-7333 - Office
505-672-8213 - Mobile

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[Douglas Roberts-2]

I don't know, I don't speak Haskell.

--Doug

On Sat, Apr 13, 2013 at 3:29 PM, Nicholas Thompson <[hidden email]> wrote:

Could be!

 

Ok.  Now that that is behind us, what did the message mean?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Saturday, April 13, 2013 3:02 PM

To: The Friday Morning Applied Complexity Coffee Group

Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Nick,

 

I surprised that you are not more conversant  in computer languages.  You're always, well, niggling about the meaning of this word, or that one in the context of this or that conversation.

 

With computer languages, there are very few ambiguities, contextual or other wise. Kind of like mathematics. For one as worried as you often appear to be about the true meaning of the written word, I would have thought that you would positively revel at the ability to express yourself with nearly absolute crystal clarity, no ambiguities whatsoever.

 

Could it be that you seek out the ambiguities that are ever present  in human languages to give yourself something to pounce upon and worry over, and to provide the opportunity to engage in nearly endless conversations?

 

--Doug

On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson <[hidden email]> wrote:

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

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--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" value="[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" value="[phone]" target="_blank">505-672-8213 - Mobile

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--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" value="[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" value="[phone]" target="_blank">505-672-8213 - Mobile

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[Marcus G. Daniels]

On 4/13/13 3:29 PM, Nicholas Thompson wrote:

Now that that is behind us, what did the message mean?

Iteration is a special case of recursion, namely tail recursion.  Specifically, Glen's description of memory in the behavior of an oil filter can be handled by passing and returning an oil filter state object to the recursive functions.   It's true that with imperative programming languages like C that it is all too easy to get memory effects -- a progressively more dirty filter -- because in absence of any extra thinking or effort, there's all of the heap memory that can be mutated without any bulletproof mechanism to control its lifetime or scope.   Purely functional programming languages force use of control mechanisms over scope and lifetime.

As for the question of what constitutes an explanation for dirty oil, the engine or the absence of filtering, I'd say that's a topic not related to iteration or recursion.   There's nothing wrong with saying that "The oil is clean because it is filtered," or "The oil becomes dirty become of the activity of the engine,"  or in a deep-dive to a first-principle physical explanation of oil fluid dynamics, combustion, friction, etc. 

One way to reason about these propositions is using types.  

For example, in Haskell, types like..

type Oil = Either DirtyOil PrettyCleanOil

filterOil :: Oil -> FilterState -> (PrettyCleanOil,FilterState)

cycleEngine :: PrettyCleanOil -> Oil

..place constraints on how to put together a car.  System-level composition of these functions which fails to respect these types, simply cannot be compiled, i.e. it's proven to be internally inconsistent.

It's also possible, using a dependently typed language like ATS or Agda to define PrettyCleanOil in terms of values; it is possible for a certain, type-constrained function (certain inputs together with a set of operations) to be proven ahead of time as being able (or not) to cause a transition from PrettyCleanOil to DirtyOil.  For example, one could imagine a program that iterated `cycleEngine' a million times as compiling but a billion would not.   The reason being that a physical simulation could show that combustion and friction effects could at most produce a maximum amount of oil-dirtying per cycle.  A dependently-typed program could, for example, force the modeler to include a maintenance intervention in the simulation in order to replace the filter in order to compile.   In this way, a lot of needless simulation could be avoided.

Marcus

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[Steve Smith]

Nick -

It would be difficult to explain this (Marcus' definition of iteration vs recursion) to you without teaching you several key computer science concepts which are not necessarily difficult but are very *specific*.

The first step would be to answer your question of days ago about what a "System" is.   Physicists define System the same way Biologists (or even Social Scientists) do, just using different components and processes.   It involves the relationship between the "thing" itself (a subset of the universe) and a model that represents it. 

Therein lies two lossy compressions:  1) Reductionism is at best a convenient approximation... no subset or subsystem is completely isolated (unless perhaps somehow what is inside a black hole is isolated from what is outside, but that might be an uninteresting, degenerate case?);  2) The model is not the thing...   we've been all over this, right?  Another lossy compression/projection of reality. oh and a *third*; 3) We can only measure these quantities to some degree of precision.

In a system, a simultaneous measure every quantity of every aspect of the system is it's "state".  In practice, we can only measure some of the quantities to some precision of some of the aspects, and in fact, that is pretty much what modeling is about... choosing that subset according to various limited qualities such as what we *can* measure  and with what level of precision and with a goal in mind of answering specific questions with said model.

At this point, we are confronted with "what means State?"

Your preference for "Analytical Output" vs "State" I think reflects your attempt to think in terms of the implementation of a model (in a computer program, or human executed logic/algorithm).  The problems with "Analytical Output" in this context arise from both "Analytical" and "Output".   "Analytical" implies that the only or main value of the "state" is to do analysis on it.  In Marcus example, it's main use is to feed it right back into an iterated model... no human may ever look at this "state".  "Output" suggests (also) that the state is visible *outside* the system.   While (for analytical purposes) we might choose to capture a snapshot of the state, it is not an "output", it is just the STATE of the system (see above).

Marcus point was that in a recursive *program* (roughly a deterministic implementation rooted in formal symbol processing, of a model of some "system"), the "system" is nominally subdivided into physical or logical subsets or "subsystems" and executed *recursively* (to wit, by subdividing again until an answer can be obtained without further subdivision).  In an iterative *program*, the entire (sub) system model is executed with initial conditions (state) one time, then the resulting state of that iteration is used as the initial conditions for the *next* iteration until some convergence criteria (the state of the system ceases to change above some epsilon) is met.

I hope this helps...  and doesn't muddy the water yet more?

- Steve

I don't know, I don't speak Haskell.

--Doug

On Sat, Apr 13, 2013 at 3:29 PM, Nicholas Thompson <[hidden email]> wrote:

Could be!

 

Ok.  Now that that is behind us, what did the message mean?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Saturday, April 13, 2013 3:02 PM

To: The Friday Morning Applied Complexity Coffee Group

Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Nick,

 

I surprised that you are not more conversant  in computer languages.  You're always, well, niggling about the meaning of this word, or that one in the context of this or that conversation.

 

With computer languages, there are very few ambiguities, contextual or other wise. Kind of like mathematics. For one as worried as you often appear to be about the true meaning of the written word, I would have thought that you would positively revel at the ability to express yourself with nearly absolute crystal clarity, no ambiguities whatsoever.

 

Could it be that you seek out the ambiguities that are ever present  in human languages to give yourself something to pounce upon and worry over, and to provide the opportunity to engage in nearly endless conversations?

 

--Doug

On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson <[hidden email]> wrote:

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College to unsubscribe
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============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a moz-do-not-send="true" href="tel:[phone]" value="[phone]" target="_blank">505-455-7333 - Office
<a moz-do-not-send="true" href="tel:[phone]" value="[phone]" target="_blank">505-672-8213 - Mobile

============================================================
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Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a moz-do-not-send="true" href="tel:[phone]" value="[phone]" target="_blank">505-455-7333 - Office
<a moz-do-not-send="true" href="tel:[phone]" value="[phone]" target="_blank">505-672-8213 - Mobile

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Meets Fridays 9a-11:30 at cafe at St. John's College
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[Russ Abbott]

I would characterize the notion of state in terms of the functionality that the thing whose state we are talking about. Depending on its state, it is does and is capable of doing different things.  This is different from thinking of state in terms of measurements. This sense of state is an abstract notion and doesn't tell you how to determine the state something is in. It just tells you what I mean by state. 

• When a traffic light is in the red state it emits red light, and it is capable of changing its state to green. 
  
• When a traffic light is in the green state it emits green light, and it is capable of changing its state to yellow. 
  
• When a traffic light is in the yellow state it emits yellow light, and it is capable of changing its state to red. 
  

Since I haven't been following this discussion at all carefully, perhaps this isn't what you are talking about. In that case, sorry for the intrusion.

-- Russ

 

-- Russ Abbott
_____________________________________________

  Professor, Computer Science
  California State University, Los Angeles

  My paper on how the Fed can fix the economy: ssrn.com/abstract=1977688
  Google voice: 747-999-5105

  Google+: plus.google.com/114865618166480775623/

  vita:  sites.google.com/site/russabbott/

  CS Wiki and the courses I teach
_____________________________________________ 

On Sat, Apr 13, 2013 at 7:46 PM, Steve Smith <[hidden email]> wrote:

Nick -

It would be difficult to explain this (Marcus' definition of iteration vs recursion) to you without teaching you several key computer science concepts which are not necessarily difficult but are very *specific*.

The first step would be to answer your question of days ago about what a "System" is.   Physicists define System the same way Biologists (or even Social Scientists) do, just using different components and processes.   It involves the relationship between the "thing" itself (a subset of the universe) and a model that represents it. 

Therein lies two lossy compressions:  1) Reductionism is at best a convenient approximation... no subset or subsystem is completely isolated (unless perhaps somehow what is inside a black hole is isolated from what is outside, but that might be an uninteresting, degenerate case?);  2) The model is not the thing...   we've been all over this, right?  Another lossy compression/projection of reality. oh and a *third*; 3) We can only measure these quantities to some degree of precision.

In a system, a simultaneous measure every quantity of every aspect of the system is it's "state".  In practice, we can only measure some of the quantities to some precision of some of the aspects, and in fact, that is pretty much what modeling is about... choosing that subset according to various limited qualities such as what we *can* measure  and with what level of precision and with a goal in mind of answering specific questions with said model.

At this point, we are confronted with "what means State?"

Your preference for "Analytical Output" vs "State" I think reflects your attempt to think in terms of the implementation of a model (in a computer program, or human executed logic/algorithm).  The problems with "Analytical Output" in this context arise from both "Analytical" and "Output".   "Analytical" implies that the only or main value of the "state" is to do analysis on it.  In Marcus example, it's main use is to feed it right back into an iterated model... no human may ever look at this "state".  "Output" suggests (also) that the state is visible *outside* the system.   While (for analytical purposes) we might choose to capture a snapshot of the state, it is not an "output", it is just the STATE of the system (see above).

Marcus point was that in a recursive *program* (roughly a deterministic implementation rooted in formal symbol processing, of a model of some "system"), the "system" is nominally subdivided into physical or logical subsets or "subsystems" and executed *recursively* (to wit, by subdividing again until an answer can be obtained without further subdivision).  In an iterative *program*, the entire (sub) system model is executed with initial conditions (state) one time, then the resulting state of that iteration is used as the initial conditions for the *next* iteration until some convergence criteria (the state of the system ceases to change above some epsilon) is met.

I hope this helps...  and doesn't muddy the water yet more?

- Steve

I don't know, I don't speak Haskell.

--Doug

On Sat, Apr 13, 2013 at 3:29 PM, Nicholas Thompson <[hidden email]> wrote:

Could be!

 

Ok.  Now that that is behind us, what did the message mean?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Saturday, April 13, 2013 3:02 PM

To: The Friday Morning Applied Complexity Coffee Group

Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Nick,

 

I surprised that you are not more conversant  in computer languages.  You're always, well, niggling about the meaning of this word, or that one in the context of this or that conversation.

 

With computer languages, there are very few ambiguities, contextual or other wise. Kind of like mathematics. For one as worried as you often appear to be about the true meaning of the written word, I would have thought that you would positively revel at the ability to express yourself with nearly absolute crystal clarity, no ambiguities whatsoever.

 

Could it be that you seek out the ambiguities that are ever present  in human languages to give yourself something to pounce upon and worry over, and to provide the opportunity to engage in nearly endless conversations?

 

--Doug

On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson <[hidden email]> wrote:

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College to unsubscribe
http://redfish.com/mailman/listinfo/friam_redfish.com


============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" value="[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" value="[phone]" target="_blank">505-672-8213 - Mobile

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" value="[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" value="[phone]" target="_blank">505-672-8213 - Mobile

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

[Nick Thompson]

I guess I would call this a functional state.   Or perhaps a disposition. 

 

But what is interesting to me about this usage of state is the following:

 

. This sense of state is an abstract notion and doesn't tell you how to determine the state something is in. It just tells you what I mean by state

 

Russ, in your graduate training, did anybody beat you over the head with the terms “hypothetical construct” and “intervening variable”?

 

So the lurking question, here, for a behaviorist, is what could meaning mean but the measures by which one accesses it.  I think it probably means the network of relations in which the concept resides.  So you can have a conversation about unicorns, not because we have ever seen one, but because the concept of a unicorn lives in a network of concepts that are more closely related to things we have seen. 

 

Nick  

 

From: Friam [mailto:[hidden email]] On Behalf Of Russ Abbott
Sent: Saturday, April 13, 2013 9:16 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Systems, State, Recursion, Iteration.

 

I would characterize the notion of state in terms of the functionality that the thing whose state we are talking about. Depending on its state, it is does and is capable of doing different things.  This is different from thinking of state in terms of measurements. This sense of state is an abstract notion and doesn't tell you how to determine the state something is in. It just tells you what I mean by state

. 

• When a traffic light is in the red state it emits red light, and it is capable of changing its state to green. 
• When a traffic light is in the green state it emits green light, and it is capable of changing its state to yellow. 
• When a traffic light is in the yellow state it emits yellow light, and it is capable of changing its state to red. 

Since I haven't been following this discussion at all carefully, perhaps this isn't what you are talking about. In that case, sorry for the intrusion.

 

-- Russ

 

 

 

-- Russ Abbott
_____________________________________________

  Professor, Computer Science
  California State University, Los Angeles

 

  My paper on how the Fed can fix the economy: ssrn.com/abstract=1977688
  Google voice: 747-999-5105

  Google+: plus.google.com/114865618166480775623/

  vita:  sites.google.com/site/russabbott/

  CS Wiki and the courses I teach
_____________________________________________ 

 

On Sat, Apr 13, 2013 at 7:46 PM, Steve Smith <[hidden email]> wrote:

Nick -

It would be difficult to explain this (Marcus' definition of iteration vs recursion) to you without teaching you several key computer science concepts which are not necessarily difficult but are very *specific*.

The first step would be to answer your question of days ago about what a "System" is.   Physicists define System the same way Biologists (or even Social Scientists) do, just using different components and processes.   It involves the relationship between the "thing" itself (a subset of the universe) and a model that represents it. 

Therein lies two lossy compressions:  1) Reductionism is at best a convenient approximation... no subset or subsystem is completely isolated (unless perhaps somehow what is inside a black hole is isolated from what is outside, but that might be an uninteresting, degenerate case?);  2) The model is not the thing...   we've been all over this, right?  Another lossy compression/projection of reality. oh and a *third*; 3) We can only measure these quantities to some degree of precision.

In a system, a simultaneous measure every quantity of every aspect of the system is it's "state".  In practice, we can only measure some of the quantities to some precision of some of the aspects, and in fact, that is pretty much what modeling is about... choosing that subset according to various limited qualities such as what we *can* measure  and with what level of precision and with a goal in mind of answering specific questions with said model.

At this point, we are confronted with "what means State?"

Your preference for "Analytical Output" vs "State" I think reflects your attempt to think in terms of the implementation of a model (in a computer program, or human executed logic/algorithm).  The problems with "Analytical Output" in this context arise from both "Analytical" and "Output".   "Analytical" implies that the only or main value of the "state" is to do analysis on it.  In Marcus example, it's main use is to feed it right back into an iterated model... no human may ever look at this "state".  "Output" suggests (also) that the state is visible *outside* the system.   While (for analytical purposes) we might choose to capture a snapshot of the state, it is not an "output", it is just the STATE of the system (see above).

Marcus point was that in a recursive *program* (roughly a deterministic implementation rooted in formal symbol processing, of a model of some "system"), the "system" is nominally subdivided into physical or logical subsets or "subsystems" and executed *recursively* (to wit, by subdividing again until an answer can be obtained without further subdivision).  In an iterative *program*, the entire (sub) system model is executed with initial conditions (state) one time, then the resulting state of that iteration is used as the initial conditions for the *next* iteration until some convergence criteria (the state of the system ceases to change above some epsilon) is met.

I hope this helps...  and doesn't muddy the water yet more?

- Steve

I don't know, I don't speak Haskell.

 

--Doug

On Sat, Apr 13, 2013 at 3:29 PM, Nicholas Thompson <[hidden email]> wrote:

Could be!

 

Ok.  Now that that is behind us, what did the message mean?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Saturday, April 13, 2013 3:02 PM

To: The Friday Morning Applied Complexity Coffee Group

Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Nick,

 

I surprised that you are not more conversant  in computer languages.  You're always, well, niggling about the meaning of this word, or that one in the context of this or that conversation.

 

With computer languages, there are very few ambiguities, contextual or other wise. Kind of like mathematics. For one as worried as you often appear to be about the true meaning of the written word, I would have thought that you would positively revel at the ability to express yourself with nearly absolute crystal clarity, no ambiguities whatsoever.

 

Could it be that you seek out the ambiguities that are ever present  in human languages to give yourself something to pounce upon and worry over, and to provide the opportunity to engage in nearly endless conversations?

 

--Doug

On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson <[hidden email]> wrote:

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College to unsubscribe
http://redfish.com/mailman/listinfo/friam_redfish.com


============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" target="_blank">505-672-8213 - Mobile

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" target="_blank">505-672-8213 - Mobile

 

============================================================

FRIAM Applied Complexity Group listserv

Meets Fridays 9a-11:30 at cafe at St. John's College

to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
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[Nick Thompson]

Thanks, Steve.  Will ponder all of this.  Nick

 

From: Friam [mailto:[hidden email]] On Behalf Of Steve Smith
Sent: Saturday, April 13, 2013 8:47 PM
To: The Friday Morning Applied Complexity Coffee Group
Subject: [FRIAM] Systems, State, Recursion, Iteration.

 

Nick -

It would be difficult to explain this (Marcus' definition of iteration vs recursion) to you without teaching you several key computer science concepts which are not necessarily difficult but are very *specific*.

The first step would be to answer your question of days ago about what a "System" is.   Physicists define System the same way Biologists (or even Social Scientists) do, just using different components and processes.   It involves the relationship between the "thing" itself (a subset of the universe) and a model that represents it. 

Therein lies two lossy compressions:  1) Reductionism is at best a convenient approximation... no subset or subsystem is completely isolated (unless perhaps somehow what is inside a black hole is isolated from what is outside, but that might be an uninteresting, degenerate case?);  2) The model is not the thing...   we've been all over this, right?  Another lossy compression/projection of reality. oh and a *third*; 3) We can only measure these quantities to some degree of precision.

In a system, a simultaneous measure every quantity of every aspect of the system is it's "state".  In practice, we can only measure some of the quantities to some precision of some of the aspects, and in fact, that is pretty much what modeling is about... choosing that subset according to various limited qualities such as what we *can* measure  and with what level of precision and with a goal in mind of answering specific questions with said model.

At this point, we are confronted with "what means State?"

Your preference for "Analytical Output" vs "State" I think reflects your attempt to think in terms of the implementation of a model (in a computer program, or human executed logic/algorithm).  The problems with "Analytical Output" in this context arise from both "Analytical" and "Output".   "Analytical" implies that the only or main value of the "state" is to do analysis on it.  In Marcus example, it's main use is to feed it right back into an iterated model... no human may ever look at this "state".  "Output" suggests (also) that the state is visible *outside* the system.   While (for analytical purposes) we might choose to capture a snapshot of the state, it is not an "output", it is just the STATE of the system (see above).

Marcus point was that in a recursive *program* (roughly a deterministic implementation rooted in formal symbol processing, of a model of some "system"), the "system" is nominally subdivided into physical or logical subsets or "subsystems" and executed *recursively* (to wit, by subdividing again until an answer can be obtained without further subdivision).  In an iterative *program*, the entire (sub) system model is executed with initial conditions (state) one time, then the resulting state of that iteration is used as the initial conditions for the *next* iteration until some convergence criteria (the state of the system ceases to change above some epsilon) is met.

I hope this helps...  and doesn't muddy the water yet more?

- Steve

I don't know, I don't speak Haskell.

 

--Doug

On Sat, Apr 13, 2013 at 3:29 PM, Nicholas Thompson <[hidden email]> wrote:

Could be!

 

Ok.  Now that that is behind us, what did the message mean?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Saturday, April 13, 2013 3:02 PM

To: The Friday Morning Applied Complexity Coffee Group

Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Nick,

 

I surprised that you are not more conversant  in computer languages.  You're always, well, niggling about the meaning of this word, or that one in the context of this or that conversation.

 

With computer languages, there are very few ambiguities, contextual or other wise. Kind of like mathematics. For one as worried as you often appear to be about the true meaning of the written word, I would have thought that you would positively revel at the ability to express yourself with nearly absolute crystal clarity, no ambiguities whatsoever.

 

Could it be that you seek out the ambiguities that are ever present  in human languages to give yourself something to pounce upon and worry over, and to provide the opportunity to engage in nearly endless conversations?

 

--Doug

On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson <[hidden email]> wrote:

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College to unsubscribe
http://redfish.com/mailman/listinfo/friam_redfish.com


============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" target="_blank">505-672-8213 - Mobile

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" target="_blank">505-672-8213 - Mobile

============================================================

FRIAM Applied Complexity Group listserv

Meets Fridays 9a-11:30 at cafe at St. John's College

to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

============================================================
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Meets Fridays 9a-11:30 at cafe at St. John's College
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[Russ Abbott]

Never beaten over the head with “hypothetical construct” or “intervening variable”. My notion of state is basic theoretical computer science. How an automaton (a formally defined mechanism such as a Turing Machine, Finite Automaton, etc.) reacts to its input depends on its state. This isn't intended to be particularly sophisticated. It's just a technique used when specifying how things interact with their environments. 

When a traffic light that controls a crosswalk is in the green state (in your direction) and you press the cross button, it ignores that input. When it's in its red state (in your direction) and you press the cross button, it starts counting down to turning green. How long the countdown will be depends on another element of its state: how much time has passed since the most recent green.

 

-- Russ Abbott
_____________________________________________

  Professor, Computer Science
  California State University, Los Angeles

  My paper on how the Fed can fix the economy: ssrn.com/abstract=1977688
  Google voice: 747-999-5105

  Google+: plus.google.com/114865618166480775623/

  vita:  sites.google.com/site/russabbott/

  CS Wiki and the courses I teach
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On Sat, Apr 13, 2013 at 8:48 PM, Nicholas Thompson <[hidden email]> wrote:

Thanks, Steve.  Will ponder all of this.  Nick

 

From: Friam [mailto:[hidden email]] On Behalf Of Steve Smith
Sent: Saturday, April 13, 2013 8:47 PM

To: The Friday Morning Applied Complexity Coffee Group

Subject: [FRIAM] Systems, State, Recursion, Iteration.

 

Nick -

It would be difficult to explain this (Marcus' definition of iteration vs recursion) to you without teaching you several key computer science concepts which are not necessarily difficult but are very *specific*.

The first step would be to answer your question of days ago about what a "System" is.   Physicists define System the same way Biologists (or even Social Scientists) do, just using different components and processes.   It involves the relationship between the "thing" itself (a subset of the universe) and a model that represents it. 

Therein lies two lossy compressions:  1) Reductionism is at best a convenient approximation... no subset or subsystem is completely isolated (unless perhaps somehow what is inside a black hole is isolated from what is outside, but that might be an uninteresting, degenerate case?);  2) The model is not the thing...   we've been all over this, right?  Another lossy compression/projection of reality. oh and a *third*; 3) We can only measure these quantities to some degree of precision.

In a system, a simultaneous measure every quantity of every aspect of the system is it's "state".  In practice, we can only measure some of the quantities to some precision of some of the aspects, and in fact, that is pretty much what modeling is about... choosing that subset according to various limited qualities such as what we *can* measure  and with what level of precision and with a goal in mind of answering specific questions with said model.

At this point, we are confronted with "what means State?"

Your preference for "Analytical Output" vs "State" I think reflects your attempt to think in terms of the implementation of a model (in a computer program, or human executed logic/algorithm).  The problems with "Analytical Output" in this context arise from both "Analytical" and "Output".   "Analytical" implies that the only or main value of the "state" is to do analysis on it.  In Marcus example, it's main use is to feed it right back into an iterated model... no human may ever look at this "state".  "Output" suggests (also) that the state is visible *outside* the system.   While (for analytical purposes) we might choose to capture a snapshot of the state, it is not an "output", it is just the STATE of the system (see above).

Marcus point was that in a recursive *program* (roughly a deterministic implementation rooted in formal symbol processing, of a model of some "system"), the "system" is nominally subdivided into physical or logical subsets or "subsystems" and executed *recursively* (to wit, by subdividing again until an answer can be obtained without further subdivision).  In an iterative *program*, the entire (sub) system model is executed with initial conditions (state) one time, then the resulting state of that iteration is used as the initial conditions for the *next* iteration until some convergence criteria (the state of the system ceases to change above some epsilon) is met.

I hope this helps...  and doesn't muddy the water yet more?

- Steve

I don't know, I don't speak Haskell.

 

--Doug

On Sat, Apr 13, 2013 at 3:29 PM, Nicholas Thompson <[hidden email]> wrote:

Could be!

 

Ok.  Now that that is behind us, what did the message mean?

 

N

 

From: Friam [mailto:[hidden email]] On Behalf Of Douglas Roberts
Sent: Saturday, April 13, 2013 3:02 PM

To: The Friday Morning Applied Complexity Coffee Group

Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

 

Nick,

 

I surprised that you are not more conversant  in computer languages.  You're always, well, niggling about the meaning of this word, or that one in the context of this or that conversation.

 

With computer languages, there are very few ambiguities, contextual or other wise. Kind of like mathematics. For one as worried as you often appear to be about the true meaning of the written word, I would have thought that you would positively revel at the ability to express yourself with nearly absolute crystal clarity, no ambiguities whatsoever.

 

Could it be that you seek out the ambiguities that are ever present  in human languages to give yourself something to pounce upon and worry over, and to provide the opportunity to engage in nearly endless conversations?

 

--Doug

On Sat, Apr 13, 2013 at 2:05 PM, Nicholas Thompson <[hidden email]> wrote:

Can anybody translate this for a non programmer person?

N

-----Original Message-----
From: Friam [mailto:[hidden email]] On Behalf Of Marcus G.
Daniels
Sent: Saturday, April 13, 2013 1:10 PM
To: [hidden email]
Subject: Re: [FRIAM] Tautologies and other forms of circular reasoning.

On 4/12/13 5:40 PM, glen wrote:
> Iteration is most aligned with stateful repetition. Recursion is most
> aligned with stateless repetition.
Purely functional constructs can capture iteration, though.

$ cat foo.hs
import Control.Monad.State
import Control.Monad.Loops

inc :: State Int Bool
inc = do i <- get
          put (i + 1)
          return (i < 10)

main = do
   putStrLn (show (runState (whileM inc get) 5)) $ ghc --make foo.hs $ ./foo
([6,7,8,9,10],11)

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--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" target="_blank">505-672-8213 - Mobile

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Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

--

Doug Roberts
[hidden email]

http://parrot-farm.net/Second-Cousins

<a href="tel:[phone]" target="_blank">505-455-7333 - Office
<a href="tel:[phone]" target="_blank">505-672-8213 - Mobile

============================================================

FRIAM Applied Complexity Group listserv

Meets Fridays 9a-11:30 at cafe at St. John's College

to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

 

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com

============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com