[FOM] Putnam Replies

[Charles Silver]

>
>> Putnam's Reply to David Macarthur
>>
>> David Macarthur raises the question “Why do I want to keep the term
>> ‘metaphysics’?”. A general answer is that I am interested in
>> questions that are traditionally called “metaphysical questions”,

	But should they be called "metaphysical" even if they have been in  
the past?
	
	It was due to the reigning metaphysical view of "Mechanism" which  
tortured Newton about his theory of gravitation, since his theory  
seemed to require "action at a distance," which Mechanism outlawed.    
In places, Newton says that gravitation provided no explanation  
whatever.   In other places, he seems to want to accept it as an  
explanation, though even then he has doubts.   It was in this case a   
deleterious metaphysical world view which prevented Newton's full  
acceptance of his own theory.  [See Dijksterhuis's _The Mechanization  
of the World Picture_.]

>> [Deleted]

	Putnam quotes J.S. Bell as "tr[ying] to understand physics  
realistically,
>>  saying “We want to understand quantum mechanics not
>> just as a prediction tool, we want a picture of the world, we want
>> to make sense of a world in which this crazy tool works”,...

	Yet, there are multiple interpretations of quantum mechanics by  
multiple physicists, and certainly many of them are weird--one might  
even say ridiculous from a "realistic" point of view.   It seems  
obvious that mathematics as cleaved to physical formulas is what  
constitutes physical theories these days, not any "metaphysical"  
picture of the world, such as one, say, of the Pre-Socratic  
philosophers.

>> a great
>> many good things happened in physics that would not have happened
>> otherwise.

	I think it's true that having a strong metaphysical picture can aid  
discoveries, but they can also get in the way.   Einstein's insistence  
on the Lord not playing dice is an example of realism preventing him  
from making further physical advances.    So, metaphysical myths can  
sometimes aid and sometimes hinder.

	In this forum, realism with regard to mathematical truths has been  
frequently denounced.   In particular, many have adopted a  
constructivist view opposing the use of LEM (the law of the excluded  
middle).

[Deleted]

>>  I
>> don’t believe that the so-called “Many-Worlds interpretation” of
>> quantum mechanics works,...

	So, it doesn't "work" according to Putnam.  That sounds like  
instrumentalism to me, not realism.


>> but that  attempt did lead to the discovery
>> of the decoherence theorems which certainly are going to be part of
>> any explanation of why the macroscopic world we experience is as it
>> is,and that interpretation was proposed because its inventors, Hugh
>> Everett III, and  Cecil M. DeWitt were willing to take the question
>> as to what quantum mechancs actually says about reality seriously.

	One example of a "metaphysical interpretation" being helpful, despite  
Putnam's view that it doesn't work, presumably because he believes  
this interpretation must be dropped--and another metaphysical view to  
be adopted?-- in order to explain other phenomena.

>>
>> And the list goes on and on.

	But it seems as though "the list" represents metaphysical *myths,*  
which (again) are sometimes helpful, other times not.

[Deleted]

>> In fact, the very philosophers who denounce metaphysics always get
>> entangled with it. Carnap had a metaphysical view of mathematics,
>> and it doesn’t work.

	Something seems wrong with connecting the two sentences above.  [?]

[Deleted]

	Putnam says that the mathematical views of that "great philosopher"  
Wittgenstein who "was deeply in
the grip of a metaphysical picture" were "junk".

Charlie Silver