From: jhaukioj@sara.cc.utu.fi
Newsgroups: sci.philosophy.meta
Subject: Re: Having to believe
Date: 14 Aug 92 20:46:33 GMT
Organization: University of Turku, Finland

Sorry for the delay, but the news server here has just started functioning
again after a blackout of two or three weeks. 

In article <denmckinnon.3.712662764@halls1.cc.monash.edu.au>, denmckinnon@halls1.cc.monash.edu.au (NEIL MCKINNON) writes:
>>> I was wondering what the important differences are between your anti-realist 
>>> position here and a realist position.  My reading on this topic is probably 
>>> fairly limited, but as far as I can see the anti-realism of, say, Dummett >>>>> and Putnam is ultimately based on intuitions that truth ought not be non-
>>> epistemic.  Their semantics for truth seemed quite similar to me.  For 
>>> Putnam, a sentence is true only if it is part of an Ideal theory (i.e one 
>>> that maximally satisfies observable evidence and maximally satisfies our 
>>> constraints on theory acceptance, like simplicity).  For Dummett a sentence 
>>> is true only if it is conclusively verifiable (which comes to it being a 
>>> sentence in an Ideal Theory of the Universe).  Once you make truth 
>>> epistemic, what you are left with is some sort of coherence theory of truth, 
>>> whereby any consistent set of beliefs is true.  The objection to this is
 
>>Not *any* consistent set of beliefs. The body of beliefs must also be
>>consistent with observations. Maybe this is what you meant, but then it would be
>>more reasonable to talk of judgements instead of beliefs.

I was asked what I tried to accomplish by distinguishing between beliefs and
judgements. I was certainly not trying to escape to an "abyss of confusions
with our concepts". What I *was* trying to do was to reduce the risk of
misunderstanding. The term "judgement" covers much more easily such things as
seeing that it is raining, seeing the tracks of sub-atomic particles etc. Talk
of "observational judgements" is a lot more natural than talk of "observational
beliefs" (at least this is how it seems to me). This change in terminology, in
my opinion, helps to keep in mind that true beliefs must cohere both with
each other *and* our experiences.   
 
>Yes, I was wrong to say that Putnam's view of truth simply reduces to a 
>coherence theory.  Clearly it does not.  What I should have said, 
>rather, is that it is ultimately open to the same objection, due to 
>the fact that we may never be able to single out one theory in particular 
>as ideal, and further, that there may be a number of theories which are 
>contradictory yet indistinguishably ideal. 
> 
> 
>>I don't see why this should worry the anti-realist too much, because s/he 
>>is not saying that we have a free choice between different (consistent) 
>>sets of beliefs or conceptual systems. What the anti-realist (at least of the 
>>Putnamian type, if I am not mistaken) *is* saying is that we can't 
>>judge the truth or falsity of our beliefs outside the scheme of 
>>description that we are using. This seems to me to suffice to counter
>>the above objection that anti-realism would lead to the possible 
>>truth of (~A & A). This objection makes sense only if we assume that
>>there might be different ideal theories which would all be consistent with all
>>possible evidence. Even then I don't see any guarantee that the negation of a
>>true judgement in one such theory would even necessarily be expressible in
>>another. And even if it were, this need not worry the anti-realist, because
>>*inside* an ideal theory, (~A & A) can not be true.
> 
>I don't think you have really answered the objection.  I was talking 
>meta-theoretically, and what you have suggested in the last sentence is 
>merely that from the perspective of a particular theory, a contradictory 
>theory cannot be true.

This meta-theoretical talk is precicely what the anti-realist is saying isn't
justified (or even meaningful). According to him/her there is no theory-
independent basis on which different theories can be compared to each other. As
for the possibility of two different ideal theories which disagree on the truth
of, say, A: I personally don't see any problem with saying that, judging from
the viewpoint of theory I, theory II is wrong about A, and vice versa.
 
> >> to me to reduce to a coherence theory, since there may be many 
>internally >> consistent theories which equally satisfy all constraints on 
>acceptance and >> yet are inconsistent with each other.  This is so because 
>an ideal theory is >> not something we have epistemic access to any more 
>than an "external >> reality".  Consequently these semantics do not make 
>truth any more >> accessible than a realist conception of truth.
> 
>>I think they do. On any sensible anti-realist conception of truth, a true 
>>judgement needs to be consistent with observable evidence. This seems to me to
>>ensure that e.g. the belief that I am now sitting by a computer is true,
>>because I don't see how any theory (in a loose sense) could be observationally
>>adequate unless it implied the truth of this belief.  
> 
>As far as I can tell, Putnam *must* say of a sentence that it is true if and 
>only if it is true of an ideal theory.  This is to avoid an objection Putnam 
>himself raised against Dummett (in Reference and Understanding).  Dummett at 
>one stage wanted to say that a sentence is true if and only if it is "
>warrantedly assertible".  The objection to any anti-realist criterion for 
>truth which is less than "conclusively verifiable" or "true in an ideal 
>theory"  is that a sentence of a certain type, or a theory, can be true at 
>one time and then false later on (or simultaneously by separated 
>societies in the same world).  So the sentence "The tree-god exists and 
>controls the elements" may have been true 15000 years ago when a tribe held 
>this belief and it seemed warranted to them.  However it is not true today, 
>since the Tree-god theory does not explain observational evidence well now.  
>But it was true then!
> 
>As far as I can tell, Putnam must also add this property to an ideal theory: 
>not only must it maximally explain all observational evidence, but it must 
>explain all *possible* observational evidence.

This depends on what you mean by "possible". Taken in a loose sense of the
word, this seems to me to be plainly false. In some sense of "possible", it
certainly is possible that gravity ceases to exist tomorrow. However, if this
doesn't happen, an ideal theory need not (should not) say anything of the 
matter. (I realise that this is a problematic example, but I hope the point is
clear. Other kinds of example would do just as fine.) So the word must be read
something like "possible-for-us-in-this-world". An account of possibility
independent of the observer and the setting is part of what the anti-realist is
denying. (No circularity here: this is not meant to be an argument for
anti-realism, but a defense of the reasonableness of the position.)
  
> This addition ensures that 
>there cannot be a host of contradictory ideal theories, all true at 
>different times, which maximally explain all observable evidence possessed 
>at their respective times.

How does it ensure that? All it ensures is that there cannot be ideal theories
which disagree on some *observational* judgement. But this is already so 
because of their idealness. Disagreement can exist on judgements which cannot
be directly observed. To block this kind of disagreement, "possible" above
should be read as "possible-on-the-basis-of-what-is-REAL-and-what-is-NOT-
REAL". This is precisely what the anti-realist is denying.
 
> Now, in
>addition to possibly not being able to distinguish between certain 
>prospective ideal theories when we have all possible observational evidence, 
>there is the problem of knowing *when* we are in possession of all 
>observable evidence.  And it seems to me that this is an insoluble problem.
> 
I think the answer is quite straightforward: never. The ideal theory is just an
idealization. This doesn't matter, however: even if we can't reach an ideal
theory, we can be justified in believing some of our theories (etc.) to be part
of an/the ideal theory.

>Hope this makes sense!
> 
>Neil.

Hope so too!

Jussi.