This paper defends the Causal Theory of Reference against the recent criticism that it imposes a priori constraints on the aims and practices of science. The metaphysical essentialism of this theory is shown to be compatible with the requirements of naturalistic epistemology. The theory is nevertheless unable to forestall the problem of incommensurability for scientific terms, because it misrepresents the conditions under which their reference is fixed. The resources of the Causal Theory of Reference and of the traditional cluster or “network” theory of meaning for handling problems of commensurability are compared, and an alternative approach is recommended.

Physicalism is an empirical theory of the mind and its place in nature. So the physicalist must show that current neuroscience does not falsify physicalism, but instead supports it. Current neuroscience shows that a nervous system is what I call a vector function system. I provide a brief outline of the resources that empirical research has made available within the constraints of the vector function approach. Then I argue that these resources are sufficient, indeed apt, for the physicalist enterprise, by offering a vector functional, hence physicalist, theory of the percept—the perceptual experience itself, a paradigm of phenomenally immediate, introspectively accessible consciousness.

Sober (1984) has considered the problem of determining the evidential support, in terms of likelihood, for a hypothesis that is incomplete in the sense of not providing a unique probability function over the event space in its domain. Causal hypotheses are typically like this because they do not specify the probability of their initial conditions. Sober's (1984) solution to this problem does not work, as will be shown by examining his own biological examples of common cause explanation. The proposed solution will lead to the conclusion, contra Sober, that common cause hypotheses explain statistical correlations and not matchings between event tokens.

Causal decision theory produces decision instability in cases such as Death in Damascus where a decision itself provides evidence concerning the utility of options. Several authors have proposed ways of handling this instability. William Harper (1985 and 1986) advances one of the most elegant proposals. He recommends maximizing causal expected utility among the options that are causally ratifiable. Unfortunately, Harper's proposal imposes certain restrictions; for instance, the restriction that mixed strategies are freely available. To obtain a completely general method of handling decision instability, I step outside the confines of pure causal decision theory. I introduce a new kind of backtracking expected utility and propose maximizing it among the options that are causally ratifiable. In other words, I propose a hierarchical maximization of (1) conditional causal expected utility and (2) the new backtracking expected utility. I support this proposal with some intuitive considerations concerning the distinction between optimality and conditional optimality. And I prove that the proposal yields a solution in every finite decision problem.

When can one say that a new theory is truer than the old one it contradicts, even though neither is absolutely true? We are primarily concerned with the case in which the conflicting theories offer answers to the same questions, and so we do not introduce considerations of “logical width”. We propose that part of the new theory is truer than part of the old one when the former part gets right whatever the latter part got right while the former does not make any new mistakes. Pragmatic considerations will determine the relative importance of whatever new mistakes the new theory does make as a whole. To avoid artificial counterexamples, we restrict the parts compared to those that are “convex”. A “convex” theory is one that holds in all cases intermediate between any two cases in which it holds.

D. M. Armstrong, Michael Tooley, and Fred Dretske have recently proposed a new realist account of laws of nature, according to which laws of nature are objective relations between universals. After criticizing this account, I develop an alternative realist account, according to which (1) the nomic structure of a world is a relation between initial world-histories and world-histories, and (2) a law of nature is a fact that holds solely in virtue of nomic structure (and not, for example, in virtue of past history).

Traditionally, forces are causes of a special sort. Forces have been conceived to be the direct or immediate causes of things. Other sorts of causes act indirectly by producing forces which are transmitted in various ways to produce various effects. However, forces are supposed to act directly without the mediation of anything else.

But forces, so conceived, appear to be occult. They are mysterious, because we have no clear conception of what they are, as opposed to what they are postulated to do; and they seem to be hidden from direct observations. There is, therefore, strong initial motivation for trying to eliminate forces from physics. Furthermore, as we shall explain, powerful arguments can be mounted to show that theories with forces can always be recast as theories without them. Hence it seems that forces should be eliminated, in the interests of simplicity.

We argue, however, that forces should not be eliminated—just differently construed. For the effect of elimination is to leave us without any adequate account of the causal relationships forces were postulated to explain. And this would remain the case, even if forces could be identified with some merely dispositional properties of physical systems. In our view, forces are species of the causal relation itself, and as such have a different ontological status from the sorts of entities normally considered to be related as causes to effects.

This paper is a critical discussion of a recent article by Bas van Fraassen (1985) in which he suggests the following view: we should admit that we have no explanation of the EPR correlations, but refuse to consider the correlations as mysterious nevertheless (pp. 126–128). We shall focus on just three of the claims made by van Fraassen in support of this view. The three claims are these:

1. (1) The EPR correlations cannot be explained by signals being transmitted from one component of an EPR compound to the other (pp. 114–115).

2. (2) There is, in the EPR situation, no empirically verifiable action at a distance (pp. 124–126).

3. (3) The demand for an explanation of the EPR correlations is similar to the Aristotelian demand of the post-Newtonian proponents of the law of inertia to explain what keeps a body moving if there are no forces impressed on it (pp. 126–128).

Are probabilism and special relativity compatible? Dieks argues that they are. But the possible universe he specifies, designed to exemplify both probabilism and special relativity, either incorporates a universal “now” (and is thus incompatible with special relativity), or amounts to a many world universe (which I have discussed, and rejected as too ad hoc to be taken seriously), or fails to have any one definite overall Minkowskian-type space-time structure (and thus differs drastically from special relativity as ordinarily understood). Probabilism and special relativity appear to be incompatible after all. What is at issue is not whether “the flow of time” can be reconciled with special relativity, but rather whether explicitly probabilistic versions of quantum theory should be rejected because of incompatibility with special relativity.

In the introduction to Probabilistic Metaphysics (1984), Patrick Suppes declares his intention to refute each of five central tenets of “neotraditional metaphysics”. These tenets run as follows:

1. (1) The future is determined by the past.

2. (2) Every event has a sufficient determinant cause.

3. (3) Knowledge must be grounded in certainty.

4. (4) Scientific knowledge can in principle be made complete.

5. (5) Scientific knowledge and method can in principle be unified.