Both Aquinas and Siger were familiar with a fundamental disagreement within the earlier philosophical tradition concerning the subject of metaphysics: Is it being as being, or is it divine being? If Avicenna represented one approach to this issue, and Averroes another, both Thomas and Siger were closer to Avicennathan to Averroes in their respective solutions. Nonetheless, each resolved the issue in a distinct way. Also contested in the earlier tradition was the question of whether it belongs to physics or to metaphysics to demonstrate the existence of God. Again, Avicenna represents one side on this issue, and Averroes the other. Thomas’s personal position continues to be debated by contemporary scholars, and Siger’s seems to fall between those proposed by Avicenna and Averroes.Finally, Aquinas is credited with having developed a new and unique way of accounting for the discovery of being as being, through a process known as separatio; though there are antecedents for this in Avicenna.

Both Copleston and Duhem—I believe—claim that for Thomas Aquinas, there cannot be an infinity of anything. In this essay I argue that Thomas allows that there can be an infinity of some sorts of item and, more, that there actually are infinities of some items.

Adopting a Quinean criterion of ontological commitment, I consider Kant’s theory of our a priori knowledge of objects. I am directly concerned with the customary view that the ontology of Kant’s theory of knowledge in general, whether a priori or empirical, must be thought in terms of the a priori conditions or representations of space, time, and the categories. Accordingly, the customary view is accompanied by the customary interpretation of the ontology as consisting of Kantian“appearances” or “empirical objects.” I argue against this view and interpretation. The argument turns on the opposition between the necessity and universality of the a priori and the particularity and contingency of the existent. Its main point is that the a priori can remain necessary and universal only if the existence of objects is kept distinct from it.

In writings published after the Second World War, Martin Heidegger reinterpreted the ontological concepts by means of which he had characterized human existence in Sein und Zeit (1927), and he claimed that his new definitions revealed the real meaning of these “existentialia.” One might wonder what justifies or explains Heidegger’s surprising procedure. According to the solution to this problem proposed here, Sein und Zeit and the later works belong together as the two stages of a unified grand strategy of religious apologetics.

Quine has called the question, ‘What is there?’ the “ontological question.” But if we call this question by that name, what name shall we use for the question, ‘What are we asking when we ask “What is there?”’? I shall call it ‘the meta-ontological question’. I shall call the attempt to answer the meta-ontological question ‘meta-ontology’ and any proposed answer to it ‘a meta-ontology’. In this essay, I shall briefly sketch a meta-ontology. The meta-ontology I shall present is broadly Quinean. I am, in fact, willing to call it an exposition of Quine’s meta-ontology.

The Causal Theory of Action (CTA) is the view that x is person p’s token action if x is a movement of p’s body caused in the right way by p’s mental states which rationalise x. But there seem to be many actions which are part of a ‘larger’ action, like some particular movement executed in shaving, which are preceded by nosuch rationalising mental states. To cover these cases, the amended CTA says that some item x is a person p’s action if either the above account is true of x or x is part of a whole such that the above account is true of the whole. I discuss various senses of ‘part’ which might make the amended account plausible and conclude that the account is overly permissive; it will count as actions many items which clearly are not actions.

Materialist explanations of cause and effect tend to embrace epiphenomenalism. Those who try to avoid epiphenomenalism tend to deny either the extrinsicness of meaning or the intrinsicness of causality. I argue that to deny one or the other is equally implausible. Rather, I prefer a different strategy: accept both premises, but deny that epiphenomenalism is necessarily the conclusion. This strategy is available because the premises do not imply the conclusion without the help of an additional premise—namely, that behavior explained by reasons is caused by the reasons that explain it—and this premise is false.

Here is a dilemma. By robust common sense, the sun exists. Yet the sun is a vague object, lacking exact identity conditions, and therefore by widely accepted standards of objecthood does not exist. What goes for it goes for almost all other material things. Standard solutions to the problem of vagueness for predicates fall flat for vague objects. This paper attempts a theory which accounts for our common beliefs about vague objects by taking them as well-founded phenomena, founded on collections of more exact objects. The key notions allowing us to assign sensible truth-values to propositions about vague objects are those of truth-value density and expected truth-value. These will be illustrated in use.

In what follows, I argue that the disturbing effect of the explanatory gap arises from an illusion, an implicit expectation that all “direct grasps of the essence” of a property are achieved by a homogeneous concept-forming faculty. But there is no such faculty. The truth is that our concepts form a mixed bag, drawing on experiential states, verbal conceptions, theoretical conceptual roles, and other concept-making factors. It should not be too surprising then if some pairs of concepts, even when they directly capture the same essence, are not conceptually convertible. That would place conceptual—psychological—limits on explanation.

Quantum mechanics gives us reason to think both that the world is indeterministic, and that there are irreducibly statistical laws governing objectively chancy processes. Lewis notes that this raises a two-horned dilemma between two options deemed unacceptable: severely curtail our explanatory practices with respect to macro events, or revise our conception of the essence of chance. He maintains, however, that we can escape this dilemma by making a distinction between ‘plain’ why-questions of the simple form ‘Why did D occur?’ and ‘contrastive’ why-questions of the more complex form ‘Why did E occur rather than E*?’ I will argue that even if a chance event receives a nontrivial explanation, there is still a sense in which it happens for no reason if there is a time prior to its occurrence at which the change of its happening when it does is fixed.

In this paper, I reflect on the assumptions implicit in the psychophysical explanatory gap metaphor. There are clearly gaps in our current understanding of the psycho-physical link, but how great are they? Are they different in kind from other gaps in our understanding of the world that cause us less metaphysical and epistemological distress? Further, why are we supposed to regard the gaps in our psychological understanding differently? Rather than assess such theories of why a special gap exists, I want to take a somewhat skeptical look at the underlying assumption that the gap is all that special.

Libertarian or incompatibilist conceptions of free will (according to which free will is incompatible with determinism) have been under withering attack in the modern era of Western philosophy as obscure and unintelligible and have been dismissed as outdated by many twentieth century philosophers and scientists because of their supposed lack of fit with modern images of human beings in the natural and human sciences. In a recent book (The Significance of Free Will), I attempt to reconcile incompatibilist free will with new images of human beings emerging in the physical, biological, behavioral, cognitive, and neuro-sciences—avoiding the usual libertarian appeals to obscure or mysterious forms of agency or causation. In this paper, I extend that effort with special attention to the relation of libertarian free will to recent research on neural networks and cognition and to recent philosophical debates about freedom, control, rationality and responsibility.

In the following essay, I attempt to defend a novel position on ‘the free will problem’. In particular, I intend to provide (in outline) a position based on the descriptively central and normatively crucial role of illusion in the free will issue. Illusion, I claim, is the vital but neglected key to the free will problem. The proposed position, which can be called ‘Illusionism’, can be defended independently from its derivation from P. F. Strawson’s ‘reactive-naturalism’. However, since the role of illusion emerges only at a late stage of the train of arguments pertaining to free will, we will get to our destination by ‘free-riding’ most of the way on Strawson’s train, and then continue a bit further by ourselves, into the uncharted and dangerous Land Of Illusion.

In what follows, I argue that the thinkers of the twelfth to thirteenth century rediscovered and passed on the questions of metaphysics; in what I call the second beginning of metaphysics they also developed those questions in such a way that they could be received into the thinking of the modern era in the first place. It was precisely the theological context which forced this development and lead the theologians of the Latin West, inspired by their Arabic predecessors, to redesign metaphysics according to the rules of Aristotle’s logic and philosophy of science. Put differently, through the challenge of theology medieval metaphysics was forced to become what it had claimed to be from the onset: first philosophy.

Mellor’s theory of time includes the doctrines that (a) objectively, time does not embody tense or temporal properties other than those contained in the B-series, (b) particular objects are endurers, and (c) objectively, time does not flow. I show that these theses cannot all be true together, and that one must be rejected. Since (a) is basic to Mellor’s approach, then assuming that he would not adopt a perdurantist ontology, it follows that he should give up (c). Denying (c), however, is compatible with the essentials of his position. The falsity of (c) does not imply any version of the A-theory, and the B-theory can allow for the motion of diachronically identical entities through the dates over which their careers extend.

The view that identity can be vague is the view that there are statements of identity which are neither true or false. The view that composition can be vague is the view that unities can have borderline-constituents—elements that are neither parts nor non-parts of some larger unity. The case for vague identity is typically made by way of an argument for the vagueness of composition. In what follows, I argue that vague identity does not depend on the vagueness of composition; furthermore, the thesis that composition can be vague is actually incompatible with the thesis of vague identity.

Like ‘&’, ‘=’ is no term; it represents no extrasentential property. It marks an atomic, nonpredicative, declarative structure, sentences true solely by codesignation. Identity (its necessity and total reflexivity, its substitution rule, its metaphysical vacuity) is the objectual face of codesignation. The syntax demands pure reference, without predicative import for the asserted fact. ‘Twain is Clemens’ is about Twain, but nothing is predicated of him. Its informational value is in its ‘metailed’ semantic content: the fact of codesignation (that ‘Twain’ names Clemens) that explains what fact it asserts and why it is necessary. Critques of concepts of rigidity and elimination of singular terms result.

We can describe languages in which no words refer to objects. Such languages may contain sentences equivalent to any sentences of English, and hence may allow for as much objectivity as English does. It is wrong to try to deal with such languages by claiming that there are more objects than those accepted by common sense ontology. The correct move is rather to acknowledge a sense in which the concept of an object might have been different. A consequence of this position is that we cannot have a general semantics applicable to every describable language in which words are referentially connected to objects. The point here is not that reference may be inscrutable, but that different concepts of ‘referring to an object’ may be required for different languages.

As the Pyrrhonians made clear, reasons that adequately justify beliefs can have only three possible structures: foundationalism, coherentism, and infinitism. Infinitism—the view that adequate reasons for our beliefs are infinite and non-repeating—has never been developed carefully, much less advocated. In this paper, I will argue that only infinitism can satisfy two intuitively plausible constraints on good reasoning: the avoidance of circular reasoning and the avoidance of arbitrariness. Further, I will argue that infinitism requires serious, but salutary, revisions in our evaluation of the power of reasoning. Thus, reasoning can not provide a basis for assenting to a proposition—where to assent to a proposition, p, means to believe that we know that p. A non-dogmatic form of provisional justification will be sketched. Finally, the best objections to infinitism, including those posed by the Pyrrhonians, will be shown (at least provisionally!) to be inadequate.