I examine the current state of the debate on the metaphysics of science. In 1, I identify some of the main questions belonging to the MS, looking into the relationship between science and metaphysics. In 2, I expound the rise of the old wave in the MS, which endorses the belief that metaphysics is a guide to, or a heuristic for, science and outlines the stronger idea that metaphysics makes science possible. In 3, I examine the maximalist MS. This is (...) a contemporary revival of the old wave, reformulating the claim that metaphysics makes science possible. In 4, I look into the new wave in the MS, which argues that science is a guide to metaphysics and, more radically, that metaphysics is to be motivated by, and restricted to, science. In 5, I briefly introduce my own minimalist MS, which contends that science sets the epistemic, methodological and ontological criteria which should work as desiderata of the MS. I close this chapter in 6 with some concluding remarks. (shrink)

By quoting extensively from unpublished letters written by John von Neumann to Garret Birkhoff during the preparatory phase (in 1935) of their ground-breaking 1936 paper that established quantum logic, the main steps in the thought process leading to the 1936 Birkhoff–von Neumann paper are reconstructed. The reconstruction makes it clear why Birkhoff and von Neumann rejected the notion of quantum logic as the projection lattice of an infinite dimensional complex Hilbert space and why they postulated in their 1936 paper that (...) the quantum propositional system should be isomorphic to an abstract projective geometry. Looking at the paper now I see, that I forgot to say this, which should be said somewhere in the first §: That while common logics did apply to quantum mechanics, if the notion of simultaneous measurability is introduced as an auxiliary notion, we wished to construct a logical system, which applies directly to quantum mechanics – without any extraneous secondary notions like simultaneous measurability. And in order to have such a consequent, one-piece system of logics, we must change the classical class calculus of logics. (J. von Neumann to G. Birkhoff, November 21, 1935). (shrink)

In this paper a possible interpretative value of Aristotle’s fundamental ontological doctrine of potentiality and actuality is considered in the context of operationally undoubtedly the most successful but interpretatively still controversial theory of modern physics – quantum mechanics – especially regarding understanding the nature of the world, the phenomena of which it describes and predicts so successfully. In particular, beings of the atomic world are interpreted as real potential beings actualized by the measurement process in appropriate experimental arrangement, and the (...) problem of actual beings of the atomic world is considered in the context of Aristotle’s threefold requirement for the priority of actuality over potentiality – in time, definition or knowledge, and substantiality. (shrink)

This is the introductory essay to a collection commemorating the 100th anniversary of the publication in Mind of Bertrand Russell’s paper ‘On Denoting’.