Albert Casullo

E. J. Lowe offers an account of modal knowledge that involves two primary theses. First, the basis of modal knowledge is essential knowledge, and the source of essential knowledge is grasp of essence. Second, all empirical knowledge ultimately depends on some modal knowledge. This article assesses Lowe’s account and defends four conclusions. First, there is a tension in Lowe’s account of grasp of essence; it wavers between an undemanding version, which holds that grasp of essence requires no more than our ordinary understanding of propositions, and a more demanding version, which holds that it requires rational insight into necessary relationships between essences. Second, both versions face serious challenges. Third, Lowe’s account of knowledge of essence does not provide a basis for modal knowledge. Fourth, Lowe’s supporting argument for his second thesis contains two significant gaps and the principles necessary to close the gaps reveal further tensions in his epistemological views.

Kant contends that necessity is a criterion of the a priori—that is, that all knowledge of necessary propositions is a priori. This contention, together with two others that Kant took to be evident—we know some mathematical propositions and such propositions are necessary—leads directly to the conclusion that some knowledge is a priori. Although many contemporary philosophers endorse Kant’s criterion, supporting arguments are hard to come by. Gordon Barnes provides one of the few examples. My purpose in this chapter is to articulate and examine his argument. I have two goals in doing so. The first is to uncover several significant gaps in the argument. The second is to show that it suffers from a common defect in rationalist arguments. If the argument were successful against empiricist accounts of modal knowledge, it would apply with equal force to extant rationalist accounts of such knowledge. Hence, the cost of refuting modal empiricism is modal scepticism.

In Necessary Beings, Bob Hale addresses two questions: What is the source of necessity? What is the source of our knowledge of it? He offers novel responses to them in terms of the metaphysical notion of nature or, more familiarly, essence. In this paper, I address Hale’s response to the first question. My assessment is negative. I argue that his essentialist explanation of the source of necessity suffers from three significant shortcomings. First, Hale’s leading example of an essentialist explanation merely asserts that the nature of an entity explains some necessity, but leaves unexplained how it does so. Second, his essentialist explanation of particular necessities introduces new necessities that remain unexplained. Third, Hale’s version of essentialism presupposes a controversial metaphysical theory of properties, for which he offers no defense.

Christopher Hill contends that the metaphysical modalities can be reductively explained in terms of the subjunctive conditional and that this reductive explanation yields two tests for determining the metaphysical modality of a proposition. He goes on to argue that his reductive account of the metaphysical modalities in conjunction with his account of modal knowledge underwrites the further conclusion that conceivability does not provide a reliable test for metaphysical possibility. I argue (1) that Hill’s reductive explanation of the metaphysical modalities in terms of the subjunctive conditional does not yield a reductive explanation of knowledge of metaphysical modality in terms of knowledge of subjunctive conditionals, and (2) that his account of modal knowledge is at odds with his contention that conceivability does not provide epistemic access to metaphysical possibility.

Radical empiricism is the view that experience is the only source of knowledge. Hence, radical empiricism denies the existence of a priori knowledge. Its most famous proponents are John Stuart Mill and W. V. Quine. Although both reject a priori knowledge, they offer different empiricist accounts of the knowledge alleged by their opponents to be a priori. My primary concern in this paper is not with the cogency of their positive accounts. My focus is their arguments against a priori knowledge. My goal is to establish that although they offer very different arguments against the existence of a priori knowledge, each of their arguments suffers from a common defect. They both fail to appreciate the phenomenon of epistemic overdetermination and its role in the theory of knowledge.

Edward Erwin has recently argued against the thesis that the concepts a priori truth’ and ‘necessary truth’ are extensionally equivalent. This thesis consists of two logically independent claims: all a priori truths are necessary; and all necessary truths are a priori. Erwin leaves the first claim unchallenged and elects to devote his efforts exclusively to undermining the second. The brunt of his attack on the second claim rests on alleged unclarities in the concept of an a priori truth. He attempts to show that the E.E.H. cannot be defended upon any plausible interpretation of this concept. Although I agree that the E.E.H., as stated above, is open to Erwin's objections, I shall argue that a slightly revised version of it can be defended against these objections.

David Henderson and Terry Horgan offer a detailed account of the structure of conceptual analysis that is embedded within a more general account of a priori justification. Their account highlights an important feature of conceptual analysis that has been overlooked in the recent debate. Although it is generally recognized that conceptual analysis involves an inference from premises to the effect that some concept does (or does not) apply to a range of particular cases to a general conclusion about the nature of the concept itself, the details of that inference have not been fully articulated. Henderson and Horgan offer an articulation of the inferential connection which, taken in conjunction with their account of a priori justification, yields a startling conclusion about the epistemic status of the results of conceptual analysis. My view is that their account of a priori justification misses the mark and, as a consequence, they arrive at a conclusion about the epistemic status of the results of conceptual analysis that many will find implausible. Moreover, I fear that because many will find their overall conclusion implausible, they will either overlook or dismiss the important feature of the inferential connection that Henderson and Horgan correctly highlight. Hence, I have two goals. First, I want to track down the source of their mischaracterization of the a priori and to show why it is a mischaracterization. Second, I want to highlight the important feature of the inferential connection involved in conceptual analysis that they identify, articulate its bearing on the debate over the existence of a priori knowledge and assess its implications

This paper examines the view that ordinary particulars are complexes of universals. Russell's attempt to develop such a theory is articulated and defended against some common misinterpretations and unfounded criticisms in Section I. The next two sections address an argument which is standardly cited as the primary problem confronting the theory: (1) it is committed to the necessary truth of the principle of the identity of indiscernibles; (2) the principle is not necessarily true. It is argued in Section II that a proponent of the theory need not accept (1) and an argument against (2) is presented in Section III. The final section attempts to show that Russell's theory ultimately fails because of inadequacies in its treatment of space and time. The paper closes with a suggestion for remedying this difficulty