The contention that psychological states are multiply realizable in different substrates has been used to support the contention that neuroscience is not likely to be very useful in guiding an understanding how cognition works. But in the context of scientific research, how seriously should we really take this threat of multiple realizability? By examining how brain areas are identified in neuroscience (where the approach is comparative and employs functional criteria), we show that the skepticism about neuroscience's role in understanding cognition is misguided and that the apparent success of multiple realizability is based on methodological error. With respect to the former point, we develop and analyze a representative case in which the organization of the brain provides crucial information about the organization of the cognitive system. Then we show that the initial plausibility of claims to multiple realizability rest on (a) mismatching a broad-grained criterion (to show sameness of psychological states) with a finegrained criterion (to differentiate brain states), and (b) a failure to attend to the purposes for which taxonomies of brain and psychological states are developed.

David Malament's (1977) well-known result, which is often taken to show the uniqueness of the Poincaré-Einstein convention for defining simultaneity, involves an unwarranted physical assumption: that any simultaneity relation must remain invariant under temporal reflections. Once that assumption is removed, his other criteria for defining simultaneity are also satisfied by membership in the same backward (forward) null cone of the family of such cones with vertices on an inertial path. What is then unique about the Poincaré-Einstein convention is that it is independent of the choice of inertial path in a given inertial frame, confirming a remark in Einstein 1905. Similarly, what is unique about the backward (forward) null cone definition is that it is independent of the state of motion of an observer at a point on the inertial path.

According to the traditional presentation of Bohm's interpretation, we have immediate epistemic access to particle properties but not wavefunction properties, and mental states, pointer states, and ink patterns supervene on particle properties alone. I argue that these claims do not make physical sense, and I offer an alternative account that does.

I identify the special sort of stability (invariance, resilience, etc.) that distinguishes laws from accidental truths. Although an accident can have a certain invariance under counterfactual suppositions, there is no continuum between laws and accidents here; a law's invariance is different in kind, not in degree, from an accident's. (In particular, a law's range of invariance is not “broader”—at least in the most straightforward sense.) The stability distinctive of the laws is used to explicate what it would mean for there to be multiple grades (or degrees) of physical necessity. Whether there are is for science to discover.

Biological systems exhibit complexity at all levels of organization. It has recently been argued by Michael Behe that at the biochemical level a type of complexity exists—irreducible complexity—that cannot possibly have arisen as the result of natural, evolutionary processes and must instead be the product of (supernatural) intelligent design. Recent work on self-organizing chemical reactions calls into question Behe's analysis of the origins of biochemical complexity. His central interpretative metaphor for biochemical complexity, that of the well-designed mousetrap that ceases to function if critical parts are absent, is undermined by the observation that typical biochemical systems exhibit considerable redundancy and overlap of function. Real biochemical systems, we argue, manifest redundant complexity—a characteristic result of evolutionary processes.

Additional results are reported on the author's earlier generalization of Richard Jeffrey's solution to the problem of old evidence and new explanation.

Culp (1994) provides a defense for a form of experimental reasoning entitled ‘robustness’. Her strategy is to examine a recent episode in experimental microbiology—the case of the mistaken discovery of a bacterial organelle called a ‘mesosome’—with an eye to showing how experimenters effectively used robust experimental reasoning (or could have used robust reasoning) to refute the existence of the mesosome. My plan is to criticize Culp's assessment of the mesosome episode and to cast doubt on the epistemic significance of robustness. In turn, I present a different account of the experimental reasoning microbiologists used in arriving at the conclusion that mesosomes are artifacts. I call this form of reasoning ‘reliable process reasoning’, and close the paper with a brief discussion of how experimental microbiologists justify the claim that an experimental process is reliable.

Bodies as conceived in macroscopic theories are loosely spoken of as participating in processes. But are there any systematic reasons for regarding processes as part of the ontology of macroscopic theory? The present paper suggests that suitable motivation can be found within a project of describing a phenomenological, macroscopic ontology for equilibrium thermodynamics, and outlines some aspects of the interrelation between continuant bodies and processes.