In recent years, a large amount of scholarship has been written about St Thomas Aquinas’s views on free will and determinism. This paper is an attempt to bring some Thomist views of libertarian free will into dialogue with analytic philosopher Peter van Inwagen and his ‘mysterianism’ about free will. The thesis of this paper is that Thomist libertarians about free will are committed to Peter van Inwagen’s mysterianism about free will. The paper intends to accomplish this aim by showing how recent accounts of Thomist libertarianism cannot defeat the intuitive strength of van Inwagen’s ‘Replay argument’. The significance of this conclusion is that some Thomists are committed to mysterianism and that mysterianism is a legitimate position a Thomist can hold. This also provides evidence that the Thomist tradition can grow and be nourished by engagement with contemporary analytic philosophy.

In Chapter 6 of Objects of Credence, Anna Mahtani argues that the opacity of credence raises difficulties for the Principal Principle and proposes a revised principle relating credence and chance that avoids it. In this comment on her book, I both defend Mahtani’s proposed principle against a charge of triviality and argue that the opacity of belief does not threaten the role of chance in guiding credence.

Human experience of control is an illusion; all forms of power are a special, transient, and unstable case of protean power. Taking risks is governed by critical uncertainty less because of our lack of perfect knowledge than because the world is physically and socially indeterminate. Power, thus, lies not only in agents' potential to dominate each other, but also in acting in concert to turn propensities into reality. Radical uncertainty is, therefore, not necessarily bad news. Whether protean power endangers or protects humanity depends less on calculating risks than on agents practicing common humanity values. I revise Katzenstein's and Seybert's concepts accordingly and illustrate by discussing Artificial Intelligence's challenges to humanity.

The consequence argument attempts to show that incompatibilism is true by showing that if there is determinism, then we never had, have or will have any choice about anything. Much of the debate on the consequence argument has focused on the “beta” transfer principle, and its improvements. We shall show that on an appropriate definition of “never have had, have or will have any choice”, a version of the beta principle is a theorem given one plausible axiom for counterfactuals (weakening). Instead of being about transfer principles, the debate should be over whether the distant past and laws are up to us.

Using Jaegwon Kim’s framework of explanatory realism versus explanatory irrealism, in addition to some observations about the metaphysics and epistemology of explanation, I re-examine the disagreement between Robert Kane and Richard Double over the principle of rational explanation. I defend Kane’s account of dual rationality and argue that Double’s principle has a narrower range of application than he claims. I also show that, contrary to what Double assumes, Kane’s approach to action explanation does not lapse into a form of explanatory irrealism.

When Werner Heisenberg presented his views of the fundamental indeterminism to which his uncertainty principle pointed in the basic levels of reality described by quantum mechanics, he used the Aristotelian technical terms of act and potency, affirming that the quantum system is in potency before the measurement and that the potency was actualised when the measurement took place, speaking thus of a ‘new ontology’ of quantum mechanics. I argue that Thomas Aquinas’ Aristotelian account of indeterminism in nature, through his analysis of the notions of matter as potency and form as act, can provide a suitable framework to understand Heisenberg's philosophical intuition about the nature of quantum systems.