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From: Darren New
Subject: Re: What makes evidence valid and proper?
Date: 14 Mar 2012 02:53:09
Message: <4f604055@news.povray.org>
On 3/13/2012 11:52, Kevin Wampler wrote:
> Anyway, It seems that...

That's exactly what I was going to say. Thanks! ;-)

-- 
Darren New, San Diego CA, USA (PST)
   People tell me I am the counter-example.


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From: Ive
Subject: Re: What makes evidence valid and proper?
Date: 14 Mar 2012 18:50:40
Message: <4f6120c0$1@news.povray.org>
Am 14.03.2012 04:15, schrieb Kevin Wampler:

>> David Hume's point was: laws are general, and therefore apply to an
>> infinity of cases, so no finite number of observations increase their
>> likelihood by any amount.
>
>
> I don't follow this line of reasoning, so if it's important could you
> elaborate?

With pleasure. I already knew that condensing Hume into one sentence 
would fail but as I do definitely include him in my personal list of the 
10 most influential philosophers of all time I thought it would be a 
good idea to start with him.

Often Hume is mentioned as an empiricist (I just skimmed through the 
wikipedia article to look up his year of birth - 1711) while I would see 
his important characterization as the first *modern* skeptic and also 
one of the most radical skeptics ever. In his work "A Treatise of Human 
Nature" (quite easy to read BTW, especially given the time it was 
written, but maybe I should mention one should be in a good mood, I know 
people who do find Hume's view of the world extremely depressing) he 
demolishes all believe-systems, i.e. everything from fairy-tales to 
religion, and as he had a good run, he did not stop there and did 
deconstruct deductive and empirical methods in natural sciences as well.

The only things that do remain for Hume are algebra, geometry and a 
distant echo of humanism.

As an (absolutely incomplete) introduction what a friend of mine did 
call "Hume versus Holmes" (Doyle's Sherlock he did mean ;)):
Given a series of observations that a lady walks her dog by the market 
at 8am on Monday, it seems valid to infer that next Monday she will do 
the same, or that, in general, the lady walks her dog by the market 
every Monday.
That next Monday the lady walks by the market merely adds to the series 
of observations, it does not prove she will walk by the market every Monday.
First it is not certain, regardless of the number of observations, that 
the lady always walks by the market at 8am on Monday.
Second Hume argued that we cannot claim it is "more probable", since 
this still requires the assumption that the past predicts the future. 
Third, the observations themselves do not establish the validity of 
inductive reasoning, except inductively.

Hume was a strong influence to Kant who said something along the line: 
it was Hume who did awake me from my dogmatic slumber. Kant always did 
see it as a problem that he was not able to formulate his theories about 
science without clashing with Hume. While Kant thinks that e.g. the 
concept of space and time is given to us "a priori" for Hume space and 
time are just the *result* of two successive observations.
So Albert Einstein himself did mention David Hume as a source of 
inspiration when formulating the "Special Theory of Relativity".



>> But Emanuel Kant: In science, only observation and experiment may decide
>> upon the acceptance or rejection of scientific statements, including
>> laws and theories.
>
> Hmmmm, not entirely sure I agree with this as stated,

And you are completely right, my fault, I did forget to write down what 
I was thinking and the result is actually the opposite of what it should 
be: the logical problem of induction that did lead to Poppers 
"solution". It goes like this:
a) Hume's statement from above: laws are general, ... or better Hume's 
reasoning about induction in general.
b) Sometimes science proposes general laws at the drop of a hat, after 
even single observations.
c) Empiricism: In science, only observation and experiment may decide 
upon the acceptance or rejection of scientific statements, including
laws and theories.

But Emanuel Kant did *reject* point c in favor of a and b.
And for good reason especially from todays view: After all, astrology 
(or Adler's psychology) can produce tons of confirmation - as long as we 
limit the view to pure empiricism without Popper's "call for predictions".

Note that both Hume and Kant are always talking about natural sciences 
but not mathematics.


> Also, you put quite a bit of weight on the phrase "risky", but I'm not
> entirely sure how you precisely define the risk of a theory. I assume
> you mean that a theory is risky if it's (potentially) easy to prove
> wrong? If so this pretty well fits within the statistical view. In the
> statistical view a good theory should be "as specific as possible
> without becoming unlikely based on the evidence". Does this match what
> you're saying?

Exactly. I like the phrase "risky" for that in the same way as I 
actually do like and accept your phrase "aesthetic criteria".


-Ive


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From: Ive
Subject: Re: What makes evidence valid and proper?
Date: 14 Mar 2012 18:55:04
Message: <4f6121c8@news.povray.org>
Am 14.03.2012 05:27, schrieb Patrick Elliott:
> On 3/13/2012 6:02 PM, Ive wrote:
>> David Hume's point was: laws are general, and therefore apply to an
>> infinity of cases, so no finite number of observations increase their
>> likelihood by any amount.
> I would say that the flaw in this assumption is that there is an
> infinite number of cases. Often there is in fact a finite number of
> possible outcomes, once you apply existing laws. While one could argue
> that some sort of variation may lie "outside" those laws... unless you
> want to deny all observation, at some point the statistical odds *must*
> narrow. You get a similar dichotomy of principles when talking about how
> people think, with some arguing that there is, somehow, an infinite
> number of possibilities, and other people pointing out that the flaws in
> the human senses, mind, etc., all pretty much mean that no one is
> ***anything close*** to as unique, or unpredictable, as they presume
> themselves to be. In reality the former is likely illusion, because a)
> there is no plausible mechanism, which doesn't badly misunderstand a lot
> of things to get there, for people not being state machines, of a sort,
> and b) its only possible in control conditions, with known variables, to
> predict results, over a short span, because even in a state machine, if
> you don't know the starting state, the more complex the machine, the
> less your odds are of predicting its behavior over a longer span.

See my latest response to Kevin where I've written a bit more about Hume.

-Ive


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From: Kevin Wampler
Subject: Re: What makes evidence valid and proper?
Date: 15 Mar 2012 15:23:47
Message: <4f6241c3$1@news.povray.org>
Thanks for the interesting comments!

> Often Hume is mentioned as an empiricist (I just skimmed through the
> wikipedia article to look up his year of birth - 1711) while I would see
> his important characterization as the first *modern* skeptic and also
> one of the most radical skeptics ever. In his work "A Treatise of Human
> Nature"

I think I read this a long while ago.  At the time I remember being 
pretty underwhelmed by it, but perhaps I was just young and didn't fully 
appreciate it, so I'll put it on the queue for a reread.


> As an (absolutely incomplete) introduction what a friend of mine did
> call "Hume versus Holmes" (Doyle's Sherlock he did mean ;)):
> Given a series of observations that a lady walks her dog by the market
> at 8am on Monday, it seems valid to infer that next Monday she will do
> the same, or that, in general, the lady walks her dog by the market
> every Monday.
> That next Monday the lady walks by the market merely adds to the series
> of observations, it does not prove she will walk by the market every
> Monday.
> First it is not certain, regardless of the number of observations, that
> the lady always walks by the market at 8am on Monday.
> Second Hume argued that we cannot claim it is "more probable", since
> this still requires the assumption that the past predicts the future.
> Third, the observations themselves do not establish the validity of
> inductive reasoning, except inductively.

Not yet having reread Hume's texts on the matter myself, I have a few 
more questions/comments.  I think it's pretty obvious that you can't 
inductively deduce absolute truths, but only contingent theories. 
However, he also seems to reject inductively supporting inductive 
reasoning as "probably correct" as a case of circular reasoning.  Is 
there some reason he's ok with deductive reasoning (which surely cannot 
be supported in any less of a circular manner) but sees a problem with 
inductive reasoning?

Furthermore, I'm not entirely sure what Hume sees as the distinction 
between inductive and deductive reasoning.  The generalization of 
probable theories from finite examples is pretty well explained in a 
rigorous way by the theory of probability, and it's not like there's a 
different type of reasoning used here than in other parts of math like 
algebra, geometry, etc.  Maybe you could put forth a sort of "no free 
lunch" style argument to arrive at the same conclusion Hume does, but I 
don't get the impression that's the line of reasoning he's using.

Still, interesting stuff, I'll take a deeper look sometime since I get 
the impression that I should really reread the Hume myself if I'm going 
to ask detailed questions about it.


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