This article advertises a new account of computational implementation. According to the resemblance account, implementation is a matter of resembling a computational architecture. The resemblance account departs from previous theories by denying that computational architectures are exhausted by their formal, mathematical features. Instead, they are taken to be permeated with causality, spatiotemporality, and other nonmathematical features. I argue that this approach comports well with computer scientific practice and offers a novel response to so-called triviality arguments.

Since the discovery of dark matter in the 1980s, multiple experiments have been set up to detect dark matter particles through some other mode than gravity. Particle physicists provide detailed justifications as to why their experiments should be able to detect dark matter. I show that these justifications take on a structure different from what is often the case in experimental practice, and I argue that this is because of the limited description of dark matter. By illuminating this ‘method-driven logic’, I shed new light on questions surrounding measurement robustness and methodological pluralism in the context of dark matter research.

I examine different arguments that could be used to establish indeterminism of neurological processes. Even though scenarios where single events at the molecular level make the difference in the outcome of such processes are realistic, this falls short of establishing indeterminism, because it is not clear that these molecular events are subject to quantum mechanical uncertainty. Furthermore, attempts to argue for indeterminism autonomously (i.e., independently of quantum mechanics) fail, because both deterministic and indeterministic models can account for the empirically observed behavior of ion channels.

We argue that several apparently distinct responses to the hole argument, all invoking formal or mathematical considerations, should be viewed as a unified “mathematical response.” We then consider and rebut two prominent critiques of the mathematical response before reflecting on what is ultimately at issue in this literature.

I introduce two new tools in experimental neurobiology, optogenetics and DREADDs (designer receptors exclusively activated by designer drugs). These tools permit unprecedented control over activity in specific neurons in behaving animals. In addition to their inherent scientific interest, these tools make an important contribution to philosophy of science. They illustrate the very premises of Ian Hacking’s “microscope” argument for the relative independence of experiment from theory. This new example is important for generalizing Hacking’s argument because the background sciences (optics for microscopes, molecular biology for optogenetics, and DREADDs) and the fields of engineering producing these tools differ significantly.

The present article is written by a theoretical physicist who, for some time, has endeavored to trace the origin of the concepts and principles of quantum theory to an empirical background broader than that afforded by delicate optical and mechanical experiments on a microphysical scale involving the microconstant h. In particular he tried to reduce the dominant role of probability in modern physics to irrefutable evidence of a quite general nature. As long as quantum probability is deduced from experience with seemingly uncontrollable micro-mechanisms—think of radioactive disintegration as the most typical example—there will always be the objection that one day we still may find a hidden causality behind those small scale gambling devices called atoms, although one example of an exactly predictable atomic event would make present-day quantum theory untenable. In order to dislodge the remaining classicists from their fortress of doubt one may try to show that quantum probability is not an alibi for a temporary impotence of predicting microphysical events, but is a positive conclusion drawn from experience of a most general type, namely, from the principle of continuity, the basic tenet of the philosophy of Leibniz.

I explain and assess here Huygens’s concept of relative motion. I show that it allows him to ground most of the Law of Inertia and also to explain rotation. Thereby his concept obviates the need for Newton’s absolute space. Thus, his account is a powerful foundation for mechanics, although not without some tension.

In a deterministically evolving world, the usefulness of nontrivial probabilities can seem mysterious. I use the ‘Mentaculus’ machinery developed by David Albert and Barry Loewer to show how all probabilities in such a world can be derived from a single, initial chance event. I go on to argue that this is the only genuine chance event. Perhaps surprisingly, we have good evidence of its existence and nature. I argue that the existence of this chance event justifies our epistemic reliance on nontrivial probabilities.

At the end of the last century, there began a movement away from traditional philosophy and towards a closer contact of philosophical thought with empirical science. Philosophers following this course were met halfway by groups of scientists, mostly physicists and mathematicians, who in their own field had found themselves face to face with problems which traditionally belonged to philosophy. But since neither of these two groups was inclined to respect conventional boundaries, they joined forces and the result of their endeavors proved challenging to both philosophy and science. Various aspects and representative theses of this movement are known to-day as logical positivism, operationism, physicalism or scientific empiricism. For the movement as a whole, however, the term logical positivism is now becoming generally used. The present paper should be considered as a selective and partly historical survey of the methodological discussion in psychology from the standpoint of logical positivism.

A relationist will account for the use of ‘left’ and ‘right’ in terms of relative orientations, and other properties and relations invariant under mirroring. This analysis will apply whenever mirroring is a symmetry, so it certainly applies to classical mechanics; we argue it applies to any physical theory formulated on a manifold: it is in this sense an a priori symmetry. It should apply in particular to parity violating theories in quantum mechanics; mirror symmetry is only broken in such theories as a special symmetry.

Scientific realists contend that theory-conjunction presents a problem for empiricist conceptions of scientific knowledge and practice. Van Fraassen (1980) has offered a competing account of theory-conjunction which I argue fails to capture the mercenary character of epistemic dependence in science. Representative cases of theory-conjunction developed in the present paper show that mercenary reliance implies a “principle of epistemic symmetry” which only a realist can consistently accommodate. Finally, because the practice in question involves the conjunction of theories, a version of realism more robust than the “entity realism” of Cartwright (1983, 1989) and Hacking (1983) is required to explain the success of theory-conjunction.

Gordon Belot argues that Bayesian theory is epistemologically immodest. In response, we show that the topological conditions that underpin his criticisms of asymptotic Bayesian conditioning are self-defeating. They require extreme a priori credences regarding, for example, the limiting behavior of observed relative frequencies. We offer a different explication of Bayesian modesty using a goal of consensus: rival scientific opinions should be responsive to new facts as a way to resolve their disputes. Also we address Adam Elga’s rebuttal to Belot’s analysis, which focuses attention on the role that the assumption of countable additivity plays in Belot’s criticisms.

We introduce a dynamic model for evolutionary games played on a network where strategy changes are correlated according to degree of influence between players. Unlike the notion of stochastic stability (Foster and Young, 1990), which assumes mutations are stochastically independent and identically distributed, our framework allows for the possibility that agents correlate their strategies with the strategies of those they trust, or those who have influence over them. We show that the dynamical properties of evolutionary games, where such influence neighborhoods appear, differ dramatically from those where all mutations are stochastically independent, and establish some elementary convergence results relevant for the evolution of social institutions.

It has been argued that space-time must be inextendible—that it must be “as large as it can be” in some sense. Here, we register some skepticism with respect to this position.

Physics takes for granted that interacting systems without common history are independent, before interaction. This principle is time asymmetric, for no such restriction applies to systems without common future, after interaction. The time asymmetry is normally attributed to boundary conditions. I argue that there are two such independence principles at work in contemporary physics, one of which cannot be attributed to boundary conditions, and therefore conflicts with the assumed T-symmetry of microphysics. I note that this may have interesting ramifications in quantum mechanics.

Four techniques for measuring the masses of galaxies and larger astrophysical systems from their dynamics are discussed. Their apparent agreement is sometimes invoked as warrant for postulating huge quantities of ‘dark matter’ as the best solution to “the dynamical discrepancy,” the disparity between the amount of mass visible in large scale astrophysical systems and the amount calculated from dynamics. This paper argues that the agreement, though suggestive, is not definitive. The coincident measurements remain the best reason for preferring dark matter over revisions to General Relativity for solving the dynamical discrepancy, but the preference is only weakly warranted.

This article argues that not only are there serious internal difficulties with both Garber’s and later ‘Garber-style’ solutions of the old-evidence problem, including a recent proposal of Hartmann and Fitelson, but Garber-style approaches in general cannot solve the problem. It also follows the earlier lead of Rosenkrantz in pointing out that, despite the appearance to the contrary which inspired Garber’s nonclassical development of the Bayesian theory, there is a straightforward, classically Bayesian, solution.

Scientists employ a variety of procedures to eliminate degrees of freedom from computationally and/or analytically intractable equations. In the process, they often construct new models and discover new concepts, laws and functional relations. 1 argue these procedures embody a central notion of reduction, namely, the containment of one structure within another. However, their inclusion in the philosophical concept of reduction necessitates a reevaluation of many standard assumptions about the ontological, epistemological and functional features of a reduction. On the basis of the reevaluation, 1 advocate a continuum of reduction which proceeds from the eliminative to the constructive. The metaphysical aspects of theory use in constructive reductions are sketched.

Since the time, about a century ago, when DeMorgan (8), Boole (1) and Jevons (12), inaugurated the study of the logic of numerically definite reasoning, no one has been concerned to establish the validity rules for a very general type of numerically definite inference which is a strong analogue of the classical syllogism. The reader will readily agree that the traditional rules of syllogistic inference cannot even begin to decide whether the following proportionally quantified syllogism is a valid argument: at most 4/7 p are at most 2/3 not-m and at least 3/5 s are precisely 7/8 m, hence, at most 1/3 s are p. Likely reasons, of broad methodological interest, why this readily definable type of formal inference has been neglected will presently be proposed. Among the masters of twentieth century logic, Hilbert and Bernays (11) have, to be sure, meticulously shown how such numerically definite propositions as “at least 7 individuals have the property p” can be expressed in the predicate calculus with the use of the identity relation. They do not, since their concern with such propositions is indirect, proceed to establish a systematic calculus of classes whose “size” or extent is numerically definite. As we shall always notice, traditional logic and even ordinary Boolean algebra prefer to generalize about the laws governing the interrelationship of classes in inference systems without making any hypotheses concerning class “size” or extent except by the classical quantifier “some”, which quantifier admits the measure or extent of a class only in terms of the proposition that a given class contains or does not contain at least one member. Such a restricted admission of the relevance for inference of class size is among the fundamental reasons for the neglect of proportional quantifiers, i.e., quantifiers where numerical value is any rational number r such that 0/100 ≤ r ≤ 100/100. It can, of course, also be pointed out that the traditional syllogism and ordinary Boolean algebra do not i.e. measure, numerically define, the degree of inclusion of one class in another. Inclusion is taken either as total or partial, with no discrimination of the degree of partial inclusion.

In studying various possible physico-chemical interpretations of biological phenomena we arrived by a systematical development of what we have called “Mathematical Biophysics” at the interpretation of even such complex phenomena, as those involved in learning, Gestalt-discrimination and Gestalt-transposition. Yet, in spite of the apparent progress made along this newly trodden road, a sophisticated mind may feel that we are advancing into a peculiar “cul-de-sac.” Indeed we are discussing possible physico-chemical mechanisms underlying the discrimination, recognition and constancy-properties of various spatial forms. Yet we have not touched at all the much more fundamental question, which logically precedes all the above, namely, what can be the physicochemical interpretation of the general and primordial fact that we perceive those forms as spatial? Can we conceive any physicochemical model at all, which would illustrate how and why we experience everything as being in space?