Surprising praise of Popper by Quine

In 1976, when I delivered the John Locke Lectures at Oxford, I often spent time with Peter Strawson, and one day at lunch he made a remark I have never been able to forget. He said, "Surely half the pleasure of life is sardonic comment on the passing show".  This blog is devoted to comments, not all of them sardonic, on the passing philosophical show.

Hilary Putnam

In Pursuit of Truth (1992) Quine expressed a surprising measure of agreement with Popper - agreement which, as far as I know, has gone uncommented on all these years! 

On page 12 Quine writes “Traditional epistemology sought grounds in sensory experience capable of implying our theories about the world or at least endowing those theories  with some increment of probability. Sir Karl Popper has long stressed, to the contrary, that observation serves only to refute theory and not to support it.”

Taken at face value this looks like total agreement with Popper, and the whole section (which starts on page 9) up to this point is in perfect agreement with Popper. Moreover, the sentence that follows: “We have now been seeing in a schematic way why this is so.” (emphasis added by me), says that this is in agreement with Popper. (I noticed when I was still quite a young philosopher that Quine never employs the term “confirmation”, which is why I shudder when people call him a “confirmation holist”, just as I shudder when people call him a “meaning holist”.)

BUT

On Page 13 Quine says something that Popper would clearly disagree with:

“It is clearly true, moreover, that one continually reasons not only in refutation of hypotheses but in support of them. This, however, is a matter of arguing logically or probabilistically from other beliefs already held. It is where the technique of probability and mathematical statistics is brought to bear. Some of those supporting beliefs may be observational, but they contribute only in company with others that are theoretical. Pure observation lends only negative evidence, by refuting an observation categorical that a proposed theory implies.”

As I interpret this, Quine’s considered view is that Popper is right that observations by themselves cannot support a hypothesis, but he holds that, in conjunction with theories that we accept, but contrary to empiricism as traditionally understood, not simply because they are supported by observations (!).

For the leaders of Logical Empiricism,  Carnap and Reichenbach, it was important that there should be a formalizable notion of probability such that accepted scientific hypotheses have (ideally) a high degree of probability (Reichenbach) or a high of degree of instance-confirmation [I have forgotten what Carnap's technical term is, but I mean a high probability that the next observation will conform to the hypothesis, if the hypothesis is a universal generalization] relative to the total observational evidence.  Quine is explicitly rejecting that in those pages from Pursuit of Truth. If I am right about this, this is as sharp a break with logical positivism as the rejection of the analyticity of mathematics. And by citing Popper favorably, he emphasizes the disagreement with Carnap, since Popper and Carnap and their followers waged war on just this issue.