[hist-analytic] Reichenbach, Carnap, Positivism

Baynesr at comcast.net Baynesr at comcast.net
Mon Sep 21 09:32:15 EDT 2009

The connection between Descartes and the early protocol language advocates was certainty. In each case, you were dealing with a contingent fact that was known with certainty: that I exist is a contingent fact and, yet, I know this with greater certainty than I know the truth of the multiplication tables; similarly, 'Red, here, now' is a contingent fact I know with certainty. That was the reasoning, anyway. The comparison is quite strong, actually. I've never been completely convinced that the Cogito is a bad argument. In fact, it is a better argument in some ways than the idea that we have certainty with respect to knowledgeo of our sense data. So I'm more inclined to go with Descartes. Is there something specific about Descartes argument that you think is wrong. 

I'm unclear on what your point is with respect to probability. What motivated Reichenbach, and the Berlin positivists, was the idea that truth is not a very good concept for science to work with. Nothing is known withe certainty to be true. What is known is what is probably true. The merit is in the simple fact that science is not a body of propositions known to be true; it is a body of propositions thought to be probable. This will effect the logic of science. Truth values will be infinite between 0 and 1. There won't be two truth values. Much of this was supported by the Heisenberg business. 

By the way, the sense data program as an theory of ontology is very different from the sense data "program" of the positivists. Some positivists were realists, others were phenomenalists. In the early going, when Mach was a major player, phenomenalism was preferred because it linked up with verificationism and operationalism in physics. There were actually two historical strands: one dealing with the aftermath of the Special Theory and the other having to do with criteria of meaningfulness and the status of metaphysics - pseudo-problems and all that. 

"I think this is a mistake, and I would guess that this is a point 
which Carnap never conceded." 

First off, I think he should have conceded. In a way he did. The protocol language became a physicalist language. But this threatened the relevance of the two language approach. All we really need is the physical language. The rest is "inventory." 

I don't think the historians have figured out what was in the back of Reichenbach ingenious mind. As I see it, here is the situation. Reichenbach had seen that in dealing with the alternative views of space available, Riemannian, etc, that what you had was basically a vacuous formalism UNTIL you selected a definition of 'congruence'. Without this no geometry was testable, but more importantly the concept of 'distance' without congruence was meaningless. So you had these "analytical" truths of geometry that had no physical significance whatsover as long as this notion was not clearly defined. Now in the case of analytic sentences understood in the narrow sense as a bunch of tautologies you had much the same situation: sentences that tell us nothing about the world. So how do you get these sentences to be relevant without falling into the synthetic a priori? Answer: you say that what is essential is linking the tautologies to the world by way of the semantics of sentences at the basis of science: predictions being the most obvious. So, if I'm right, tautologies stood to predictions as geometry stood to congruence, to Reichenbach's way of thinking. Again, he was driven to much of this by way of a rejection of synthetic a priori. This is why I said this idea and not analyticity was what was important. Not much hangs on analyticity, in my opinion. Much hangs on the synthetic a priori, especially in physics. 

On contexts of justification and discovery, my view is this; to dismiss the circumstances of discovery is a "cop out." The history of science is an appropriate object of scientific investigation. So on my view saying: "Oh, I just dreamed this whole thing up in a nightmare" (something like Kekule with the carbon ring) that is just to defer investigation of possibly the most interesting types of events known to science: scientific theorizing itself. This is just more "sweep it under the rug" methodology; the sort that was encouraged by the verificationist theory of meaning. 

"What is this "real substance" that you are after?" 


On Carnap's materialism: As long as the language of science is physicalistic, which for Carnap it was, and as long as you believe that science investigates reality, it is physicalistic, to that extent Carnap was a physicalist. Indeed, if you probe more deeply his 'intensions' may prove to be physical, although I think that you are right to point out the possibility of an 'anamoly' in his thinking. By the way, his "theoretical language" IS a physicalistic language! 



----- Original Message ----- 
From: "Roger Bishop Jones" <rbj at rbjones.com> 
To: Baynesr at comcast.net 
Cc: hist-analytic at simplelists.com 
Sent: Sunday, September 20, 2009 4:01:11 AM GMT -05:00 US/Canada Eastern 
Subject: Reichenbach, Carnap, Positivism 

On Saturday 19 September 2009 14:49:11 Baynesr at comcast.net wrote: 
>"It would be interesting to know which of Carnap's theories he was 
>talking about. The Aufbau?" 
>In all likelihood, Reichenbach was talking about Carnap's view that the 
> protocol language consisted of statements about sense-data and that these 
> sense-data are immediately given and, so, in some sense incorrigible. This 
> incorrigibility throughout the history of philosophy has been compared to 
> Descartes's grounding science in the incorrigibility deriving from "I think 
> therefore I am." 

The comparison seems pretty weak to me. 
I would much more readily embrace a theory of perception in which 
sense data are incorrigible (I think such a theory is tenable, 
if you  get the details right) than accept the Cartesian cogito. 

> Historically, I don't believe there can be any question 
> about this. 

About what? 

> Reichenbach by contrast with the logical positivists averred 
> that instead of talking about truth we talk about probability. This would 
> rule out certainty with respect to the protocol language, whence the need 
> to revise the doctrine. 

I don't see that it necessarily would. 
Even if sense data are incorrigible, the inference to the external 
objects or to future sense data is not logical, and so one might 
wish to retreat on these to probabilistic statements, though as 
Hume observed, this doesn't solve the problem that the inference 
is not sound.  The inference to probability claims isn't sound either, 
unless they are just claims about the observed sense data rather than 
claims about external objects or future sense data. 
Whether or not you prefer probability statements for conclusions 
you do not have to treat sense data as probabilistic, and I can't 
see the merit in doing so. 

>Interestingly, Reichenbach notes that it was the issue of probability that 
> distanced the Berlin logical positivists from the Viennese logical 
> positivists. The Berlin people thought that *prediction* could not be 
> addressed within the framework of a logic that reduced to tautologies. 

I think this is a mistake, and I would guess that this is a point 
which Carnap never conceded. 

> What 
> Reichenbach did not appreciate, in my opinion, was that not only are 
> statements of the future at issue, but so are statements about the past; 
> and once you attempt to deal philosophically with the study of history you 
> are no longer in the realm of strict causation. There are symptoms of that  
> which the positivists glided over. 

But even if you were "in the realm of strict causation", causal 
inference is not logical inference. 

>One symptom is that contexts of discovery and contexts of justification were 
> sharply distinguihed. 

Sounds like a good idea to me! 

> The former became a purely psychological matter. 
> Discoveries could not in principle be predicted and might be arrived at in 
> dreams etc. 

Which surely is in fact the case? 

> But I think this is symptomatic of a weakness in positivism as 
> providing us with a world view. 

What is the weakness? 

> When we construct a theory we give reasons for making certain moves. 

Which presumably belong to the context of justification? 

> This is particularly evident in "miniature" when 
> an investigator constructs a theory as to how a crime occurred. He gives 
> reason for why a person MIGHT have done such and such. Coming up with a 
> prediction of the investrigator's inferences does not fall within the 
> purview of physical science, whence the need for the positivists to 
> jettison the signficance of the context of discovery. Herein lies the real 
> substance of what I am after; it cannot be artlessly dismissed without 
> great loss. 

I'm afraid I don't understand the point here. 
I don't understand what you mean when you say that positivists "jettisoned" 
the significance of the context of discovery, possibly because I don't 
know what you think its significance is. 

What is this "real substance" that you are after? 

>According to Reichenbach, Carnap accepted the criticisms of the protocol 
> language and made it a subdomain of the physical language; "logical 
> positivism" became "logical materialism," just another variant of an old 
> idea. 

I would not myself think Carnap a materialist. 
Even if his physicalistic language was purely materialistic, it was 
for him just one way of talking among many. 
He also endorsed a "theoretical" language, and had a well articulated 
position admitting talk about abstract entities. 

To the question of whether Carnap's mature philosophy should be called 
positivism I have given some thought, since I have taken up the 
term in my own philosophy even though my own views are on their 
face even less positivistic than Carnap. 
It is a topic I intend to address in some detail, and have started 
a web page at: 
Which, does not yet say much useful, but perhaps give a hint of direction. 

I decided to give the name "Liberal Positivism" to what you get 
be stripping negative dogmas out of the less liberal kind of 
positivism, and this then provides an account of the positivistic 
elements in Metaphysical Positivism. 
However, I have yet to come up with a description of what you have 
left when you do that, and why it is worth having. 

> I don't think Carnap was "eager" to do this; he was just being 
> honest. 

I think he was pretty eager to get things right, and to fix any 
problems in his philosophy whoever discovered them. 

> In their later years, I think both Russell's and Carnap's 
> philosophies became a wee bit sterile owing to their faith in materialism. 

Can't speak for Russell here, but I can't see the legitimacy of 
this criticism of Carnap. 

>I'm going to defer comment on the synthetic/analytic distinction. I'm not 
> sure how important it actually is. What is important to philosophy is the 
> alleged nonexistence of the synthetic a priori. Retaining or rejecting the 
> synthetic/analytic distinction is not as important as, say, definining 
> numbers in terms of classes etc. inmy opinion. 

How can you regard the synthetic/a priori as an important problem 
without recognising the importance of the analytic/synthetic distinction? 

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