Stephen Leeds

This paper is a discussion of David Albert's approach to the foundations of classical statistical menchanics. I point out a respect in which his account makes a stronger claim about the statistical mechanical probabilities than is usually made, and I suggest what might be motivation for this. I outline a less radical approach, which I attribute to Boltzmann, and I give some reasons for thinking that this approach is all we need, and also the most we are likely to get. The issue between the two accounts turns out to be one about the explanatory role probabilities play in statistical mechanics.

Constructive Empiricism, the view introduced in The Scientific Image, is a view of science, an answer to the question “what is science?” Arthur Fine’s and Paul Teller’s contributions to this symposium challenge especially two key ideas required to formu- late that view, namely the observable/unobservable and accept- ance/belief distinctions. I wish to thank them not only for their insightful critique but also for the support they include. For they illuminate and counter some misunderstandings of Constructive Empiricism along the way. That leaves me free to focus on those two main challenges. The three of us share a good deal of common history. So it is perhaps only remarkable, and not astonishing, that we now share a common leaning to Pragmatism in philosophy. Of us three I am clearly themost conservative in this respect, especially as pertaining to truth, reference, and belief.2 Arthur Fine showed very nicely how Constructive Empiricism could have been conceived under the canopy of Dewey’s Instrumentalism. Much of it could appear as a Corollary to that sort of Instrumentalism, I agree. But in fact Iwould not be happy to land in that general Pragmatist position

I argue that one good reason for Scientific Realists to be interested in correspondence theories is the hope they offer us of being able to state and defend realistic theses in the face of well-known difficulties about modern physics: such theses as, that our theories are approximately true, or that they will tend to approach the truth. I go on to claim that this hope is unlikely to be fulfilled. I suggest that Realism can still survive in the face of these difficulties, as a claim about the kind of theories we want to aim for. I relate this conception of Realism to various contemporary discussions, both by realists and antirealists.

Suppose my utilities are representable by a set of utility assignments, each defined for atomic sentences; suppose my beliefs are representable by a set of probability assignments. Then each of my utility assignments together with each of my probability assignments will determine a utility assignment to non-atomic sentences, in a familiar way. This paper is concerned with the question, whether I am committed to all the utility assignments so constructible. Richard Jeffrey (1984) says (in effect) "no", Isaac Levi (1974) says "yes". I argue for "no", and raise in passing a problem for Levi

David Malament has recently responded to David Albert's argument that classical electrodynamics is not time-reversal invariant by introducing a novel conception of time reversal, which supports the conventional view that under time reversal the magnetic field changes sign but the electric field remains unchanged. I will argue here that Malament's transformation has both passive and active versions. I will claim that the passive version is not relevant to Albert's argument, and the active version does not lead to the conventional transformation.

I propose a different way of thinking about metaphysical and physical necessity: namely that the fundamental notion of necessity is what would ordinarily be called "truth in all physically possible worlds" – a notion which includes the standard physical necessities and the metaphysical ones as well; I suggest that the latter are marked off not as a stricter kind of necessity but by their epistemic status. One result of this reconceptualization is that the Descartes-Kripke argument against naturalism need no longer trouble us. I end by relating the difference between my view and the standard view to the question, whether there could have been a different world than ours.

What are the objects of the so-called ‘propositional attitudes’ — belief, desire, and the like? One of the best-known accounts holds them to be sentences. According to this account — which I shall call the ‘linguistic theory’ — an analysis of the logical form of a sentence like John believes that the moon is roundwill see the word ‘that’ as a hidden pair of quotation marks: except for niceties of idiom, might be written John believes ‘the moon is round’. asserts that a certain relation, the ‘believes’-relation, holds between John and the sentence ‘the moon is round’.