[hist-analytic] Reichenbach, Carnap, Positivism

Roger Bishop Jones rbj at rbjones.com
Mon Nov 9 11:35:53 EST 2009

On Saturday 07 November 2009 16:07:04 Baynesr at comcast.net wrote:

> You persist in denying that Carnap's views were, at least at one point,
> very metaphysical. You need to look at the Aufbau. It is a phenomenalist
> approach to constructionism. Later he took physical objects as fundamental
> but during this period he did not. The work is one of ontology, not
> semantics. That comes after Tarski. Reichenbach would deny being a
> metaphysician, but so did Kant. What these guys say and what they do are
> different, sometimes, especially when "metaphysics" is involved.

If you want to  describe the Aufbau as metaphysics feel free, but Carnap had a 
coherent and stable conception of what metaphysics is, which dates from as 
early as 1928, and in terms of that conception the Aufbau is not metaphysics.
Most crucially, if at the time of the Aufbau you had asked Carnap:

	"do you deny the existence of anything but phenomena"

He would certainly have said "No".

The temporal sequence of beliefs which you attribute to Carnap is a fiction.
He did not change his mind about what objects were "fundamental" he never 
expressed an opinion on the matter, except to observe that he could make no 
sense of that kind of question (or perhaps more dogmatically, to deny that it 
had any meaning).

> So forget Schillp; look at the
> text. I'm not saying Carnap was exactly a Machian; indeed he was far
> more metaphysical than Mach. One might quibble with the word, but
> forget that approach. Look at the text; look at the Aufbau; it is a great
> work in reconstructive metaphysics!

This is like saying "don't worry about what Carnap means, just see what he 
says".  Its the Quinean approach to ontological commitment, in which 
regardless of what people say about their metaphysical beliefs they are held 
to be committed to the existence of an entity if they ever use language in 
which quantifiers range over that kind of entity.

This would make everyone who agrees that there is a prime number larger than 
19 into a Platonist, and everyone who engages in discussion about the 
characters in a work of fiction would on this theory be held to believe it a 
factual account.

Roger Jones

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