The nature of quantum mechanical probability has often seemed mysterious. To shed some light on this topic, the present paper analyzes the logical form of probability assignment in quantum mechanics. To begin the paper, I set out and criticize several attempts to analyze the form. I go on to propose a new form which utilizes a novel, probabilistic conditional and argue that this proposal is, overall, the best rendering of the quantum mechanical probability assignments. Finally, quantum mechanics aside, the discussion here has consequences for counterfactual logic, conditional probability, and epistemic probability.

Because most chemical reactions, by definition, cannot avoid breaking of bonds, weakly bonded species exist fleetingly in almost every chemical change. Historically, chemical quantum mechanics was aimed at explaining the nature of strong bonds. The theory involved a number of approximations to the full solution of the Schrödinger equation. The study of non-Kekulé molecules provides an opportunity to test whether modern quantum chemical computations are competent to deal with the nature of molecules with very weak bonds.

This essay explores the nature of spontaneous symmetry breaking (SSB) in connection with a cluster of interrelated concepts such as Curie's symmetry principle, ergodicity, and chance and stability in classical systems. First, a clarification of the two existing senses of SSB is provided and an argument developed for a proposal for SSB, in which not only the possibilities but also the actual breakings are referred to. Second, a detailed analysis is given of classical SSB that answers the questions: (i) how we are justified in regarding it as a matter of chance, and (ii) why the breakings in it are equally probable. The answer provides some support to the applicability of ergodicity in special systems (such as ours).

Central to Paul K. Feyerabend's philosophy of science are two theses: (1) there is no standard observation language available to science; instead, observability is to be viewed as a pragmatic matter; and (2) when considering questions of empirical significance and experimental test, the methodological unit of science is a set of inconsistent theories. I argue that the pragmatic theory of observation by itself decides neither for nor against any particular specification of meaning for an observation language; and that Feyerabend's position provides no decision procedure when two contending theories share no terms having the same meaning, and thus cannot be said to be logically incompatible. Also, Feyerabend's insistence upon falsification will force him to admit that there are relatively permanent facts available to all theories, or to abandon the idea of test as falsification and to conclude that scientific theories can only be accepted or rejected on the basis of non-evidential considerations.

Among the many dichotomous cleavages among philosophers and theologians few seem to me as questionable as the Procrustean division into supematuralists and naturalists. “Naturalism” and “supernaturalism” have become party labels whose original meanings have been lost in the heat of banner-waving and slogan shouting. Even the great minds of the past, who were innocent as yet of this philosophical two-party system, are being herded into one pen or the other. And apparently few of the penkeepers are aware of the fact, pointed out almost apologetically by Professor Randall, that “the usage is hardly fashionable abroad, even in England.” (39, p. 355) I, for one, confess that, not having been acclimatized in my European cave to this stern disjunction, I have to this day felt rather uneasy, if not evasive, at the outspoken or tacit expectation to line up with one faction or the other, much as my leanings were toward the other rather than toward the one. I therefore decided that some day I had to get to the bottom of this uneasiness.

The New Theory of Reference (NTR) of Marcus, Kripke, Kaplan, Putnam and others is a theory in the philosophy of language and there has been much debate about whether it entails the metaphysical theory of essentialism. But there has been no discussion about whether the NTR entails another metaphysical theory, the absolutist theory of time and space. It is argued in this paper that the NTR carries this entailment; the theory of time is the main focus of the paper and it is argued that the NTR entails the absolutist theory that times are event-independent moments.

The paper is inspired by the arguments raised recently by Grünbaum criticizing the current approaches of many cosmologists to the problem of spacetime singularity, matter creation and the origin of the universe. While agreeing with him that the currently favored cosmological ideas do not indicate the biblical notion of divine creation ex nihilo, I present my viewpoint on the same issues, which differs considerably from Grünbaum's. First I show that the symmetry principle which leads to the conservation law of energy is violated when the time axis is terminated at t = 0. Next I discuss why this epoch (t = 0) is more a mathematical artifact whose supposed significance may disappear when one goes beyond the classical relativistic cosmology. This is illustrated by the example of quantum cosmology.

I argue that it is possible to give an interpretation of the classical $\hslash \to 0$ limit of quantum mechanics that results in a partial explanation of the success of classical mechanics. The interpretation is novel in that it allows one to explain the success of the theoretical structure of classical mechanics. This interpretation clarifies the relationship between physical quantities and propositions in quantum theories and provides a precise notion of a quantum theory holding “approximately on certain scales.”

Animal welfare scientists face an acute version of the problem of inductive risk since they must choose whether to affirm attributions of mental states to animals in advisory contexts, knowing their decisions hold consequences for animal welfare. In such contexts, the burden of proof should be sensitive to the consequences of error, but a framework for setting appropriate burdens of proof is lacking. Through reflection on two cases—pain and cognitive enrichment—I arrive at a tentative framework based on the principle of expected welfare maximization. I then discuss the limitations of this framework and the questions it leaves open.

Scientists imagine for epistemic reasons, and these imaginings can be better or worse. But what does it mean for an imagining to be epistemically better or worse? There are at least three metaepistemological frameworks that offer different answers to this question: epistemological consequentialism, deontic epistemology, and virtue epistemology. This paper presents empirical evidence that scientists adopt each of these different epistemic frameworks with respect to imagination, but argues that the way they do this is best explained if scientists are fundamentally epistemic consequentialists about imagination.

Discussion of epistemic responsibility typically focuses on belief formation and actions leading to it. Similarly, accounts of collective epistemic responsibility have addressed the issue of collective belief formation and associated actions. However, there has been little discussion of collective responsibility for preventing epistemic harms, particularly those preventable only by the action of an unorganized group. We propose an account of collective epistemic responsibility that fills this gap. Building on Hindriks’s (2019) account of collective moral responsibility, we introduce the epistemic duty to join forces. Our theory provides an account of the responsibilities of scientists to prevent epistemic harms during inquiry.

The two books discussed here make important contributions to our understanding of the role of spacetime concepts in physical theories and how that understanding has changed during the evolution of physics. Both emphasize what can be called a ‘dynamical’ account, according to which geometric structures should be understood in terms of their roles in the laws governing matter and force. I explore how the books contribute to such a project; while generally sympathetic, I offer criticisms of some historical claims concerning Newton, and argue that the dynamical account does not undercut ontological issues as the books claim.

While discussing the work of Kuhn and Hanson, John Greenwood (1990) misidentifies the nature of the relationship between the incommensurability of theories and the theory-ladenness of observation. After pointing out this error, I move on to consider Greenwood's main argument that the Quine-Duhem thesis suffers from a form of epistemological self-defeat if it is interpreted to mean that any recalcitrant observation can always be accommodated to any theory. Greenwood finds this interpretation implausible because some adjustments to auxiliary hypotheses undermine too much of the prior observational evidence for the test theory. I argue that Greenwood mistakes the logico-metaphysical Quine-Duhem thesis for an epistemological one. All the argument he takes to undercut it actually illustrates how well the thesis works on a practical level. This is illustrated with an example from contemporary immunology.

The papers presented at the Chicago Darwin Centennial suggest a fresh approach to the philosophical problem of ends in nature. In order to avoid the implications of “teleology,” assumed to refer only to the process of evolution as directed towards goals, the discussants use “teleonomy” in reference to the biological organism as end-directed (for reproduction). They accept “teleonomy” only as descriptive, and neglect its significance for theory.

The present thesis is that each of the three recognized phases of universal evolution: inorganic, organic, and post-organic initiated by the advent of man and his culture, is characterized and made possible by the emergence of a distinctive type of teleonomic organization. While the process of evolutionary change is not itself end-directed to any goal, the end-directed structures which arise are not only “in nature” but are themselves crucial factors in evolution, since it is on them that natural selection operates. By using the concept of teleonomy, it is argued, one can avoid the issue of “mechanism” versus “teleology.”

In the usual procedure of deriving equilibrium thermodynamics from classical statistical mechanics, Gibbsian fine-grained entropy is taken as the analogue of thermodynamical entropy. However, it is well known that the fine-grained entropy remains constant under the Hamiltonian flow. In this paper it is argued that we need not search for alternatives for fine-grained entropy, nor do we have to reject Hamiltonian dynamics, in order to solve the problem of the constancy of fine-grained entropy and, more generally, to account for the non-equilibrium part of the laws of thermodynamics. Rather, we have to weaken the requirement that equilibrium be identified with a stationary probability distribution.

David Lewis's best-system analysis of laws of nature is perhaps the best known sophisticated regularity theory of laws. Its strengths are widely recognized, even by some of its ablest critics. Yet it suffers from what appears to be a glaring weakness: It seems to grant an arbitrary privilege to the standards of our own scientific culture. I argue that by reformulating, or reinterpreting, Lewis's exposition of the best-system analysis, we arrive at a view that is free of this weakness. The resulting theory of laws has the surprising consequence that the term “law of nature” is indexical.

In the course of his researches in electromagnetism and the kinetic theory of gases, James Clerk Maxwell gave some thought to the nature of science itself. His observations in this field are of interest today not only because they are his, but because they are still instructive. Maxwell's views are to be found in the many asides with which he enlivened his scientific papers and treatises and in the various articles and reviews which he prepared for more popular consumption. The topics discussed bear on his own contributions to physics; they include the logic of dynamical explanation, the method of physical analogy, and the perennial question of action at a distance versus contiguity. In the present essay, I wish to discuss Maxwell's views on dynamical explanation.

I propose, in the context of Everett interpretations of quantum mechanics, a way of understanding how there can be genuine uncertainty about the future notwithstanding that the universe is governed by known, deterministic dynamical laws, and notwithstanding that there is no ignorance about initial conditions, nor anything in the universe whose evolution is not itself governed by the known dynamical laws. The proposal allows us to draw some lessons about the relationship between chance and determinism, and to dispel one source of the tendency among Everettians to introduce consciousness as a primitive element into physical description.

After some background setting in which it is shown how Maudlin's (1989, 1990) response to the hole argument of Earman and Norton (1987) is related to that of Rynasiewicz (1994), it is argued that the syntactic proposals of Mundy (1992) and of Leeds (1995), which claim to dismiss the hole argument as an uninteresting blunder, are inadequate. This leads to a discussion of how the responses of Maudlin and Rynasiewicz relate to issues about gauge freedom and relativity principles.

The present paper is concerned chiefly with the problem of scientific prediction. It aims at a factual analysis of the processes leading to prediction, and ventures an appraisal, in the light of this analysis, of some modern and unconventional theories of probability and truth. But although prediction is here chosen as the central issue of discussion, I do not wish to imply that, in its usual sense, it is the only or even the dominant issue of scientific research.