The validity of argument by disjunctive syllogism (henceforth, DS) has been denied by proponents of relevant and paraconsistent logic (who are sometimes one and the same). DS is stigmatised for its role in inferences — most notably C.I. Lewis's derivation of that fallacy of irrelevance ex falso quodlibet (EFQ) — that involve both it and other rules of inference governing disjunction, or, to speak more precisely, other rules of inference taken to apply to the very same disjunction that obeys DS. In avoiding these inferences the road less travelled is to deny the identity rather than to deny DS: what follows is, then, an exercise in disjoining disjunctions.

By an incomplete sentence we shall understand a declarative sentence that can be used, without variation in its meaning, to make different statements in different contexts. Although the point deserves supporting argument, which we will not provide, sentences whose grammatical subjects are indexical expressions or demonstratives are obvious, plausible examples of incomplete sentences. Uttered in one context the sentence ‘He is ill’ may be used to make one statement, for example, that George is ill, while in another context the very same sentence may be used to make a quite different statement, for example, that Paul is ill.

In his Arthur Holly Compton Memorial Lecture Sir Karl Popper tackles a problem raised by Compton himself in an earlier lecture. The problem is to understand how such abstract things as aims, purposes, rules, or agreements can influence or control the movements of men, and perhaps also of animals (p. 15). To illustrate the problem Compton had remarked on the amazing faith and confidence shown by his audience and the lecture's organizer that he should arrive on the agreed date to give the lecture, considering ‘the great physical improbability that their confidence was justified’. For

Against the standard interpretation of Kant’s ‘Copernican revolution’ as the prioritization of epistemology over ontology, I argue in this paper that his critique of traditional metaphysics must be seen as a farewell to the perfectionism on which early modern rationalist ontology and epistemology are built. However, Kant does not simply replace ‘perfection’ with another fundamental concept of normativity. More radically, Kant realizes that it is not simply ideas but only the relation of ideas that can be subject to norms, and thus he shifts the focus from the reality of ideas to the validity of judgments. Section 1 of this paper clarifies the pre-Kantian role of the concept of perfection and examines Kant’s critical response to that concept. Section 2 identifies Kant’s point of departure from the Cartesian ‘way of ideas.’ Section 3 explains the key problem of his novel account of epistemic normativity. I conclude that Kant’s anti-perfectionism must be seen as the driving force behind his ‘Copernican revolution’ in order to fully appreciate his mature account of epistemic normativity.

Utilitarianism claims to be a rational moral theory in at least three ways. First, it claims to give us an objective standard of morality, a way of deciding moral issues, not in the light of what each of us happens to like or dislike, but on publicly verifiable grounds. Secondly, by offering only one criterion of morality it assures consistency. If we accept a system which invokes two or more independent principles, there is always the possibility of insoluble conflict. For example, if we take our stand on the Ten Commandments, we cannot, without divine revelation, be sure that we shall not one day find ourselves in a situation in which we must break one or other of them; and our system gives us no guide as to which we ought to break.

Suppose that in the Meditations Descartes thinks he needs to prove that his clear and distinct perceptions are true. There can be little doubt that if he does think he needs to do this, he thinks that the way to do it is to prove that ‘a non-deceiving God exists’ is true. Now suppose that Descartes does come up with such a proof. Presumably he clearly and distinctly perceives both the premisses and that ‘a non-deceiving God exists’ follows from them. But that will not suffice to prove that ‘a non-deceiving God exists’ is true. For, if there is a problem about whether clear and distinct perceptions are true, then in advance of settling it, there is a problem about whether what is proved merely on the basis of clear and distinct perceptions is true.

Professor John Wisdom holds that the reference to be found in many religious beliefs to what lies beyond the world and transcends the senses is misleading. Religious beliefs speak and, indeed, can only speak about this world, the world we know by means of the senses. The religious believer is himself misled when he describes the God he believes in as transcendent. What gives content to his beliefs is how certain things stand in this world. To appreciate these and so to embrace the beliefs in question is for a person to change in himself, to come into contact with something that lies within him. Here lies the spiritual aspect of the content of religious beliefs.

In the by now well known talks he gave at Princeton, Saul Kripke claimed that “[t]heoretical identities … are generally identities involving two rigid designators and therefore are examples of the necessary a posteriori.” (Published as “Naming and Necessity,” in G. Harmon and D. Davidson, eds., Semantics of Natural Language (Dordrecht, 1972) 253-355; (hereafter referred to as “NN”; this quote p. 331.) A rigid designator is an expression that designates the same object in all possible worlds when it is used. So Kripke is claiming that ‘Water is H20’ and ‘Heat is the motion of molecules’ are generally identities involving expressions like ‘water’ and ‘the motion of molecules’ which designate the same objects in all possible worlds. If the identity statement is true, both sides designate the same object rigidly, i.e., in all possible worlds, and therefore the statement is necessarily true. On the other hand, whether it is true is determined ultimately by appeal to experience. It follows that if true, the identity is necessary a posteriori.

Albert Casullo has argued that the propositions of arithmetic could be experientially disconfirmed, with the help of an invented scenario wherein experiences involving our standard counting procedures, as applied to collections of objects, seem to indicate that 2+2≠4. Our best response to this scenario would be, Casullo suggests, to accept the results of our standard counting procedures as correct, and give up our standard arithmetical theory. This suggestion, interestingly enough, is not as bizarre as it initially appears. But indeed a problem lies in the assumption, common to Casullo’s scenario and to his suggested resolution, that our arithmetical theory might possibly be independent of our standard counting procedures. Here I show that this assumption is incoherent, whether the independence at issue is supposed to make room for the genuine possibility that 2+2≠4, or the merely epistemic possibility that we could rationally believe that 2+2≠4: given our standard counting procedures, then (on pain of irrationality) our arithmetical theory follows.

A version of the principle of alternate possibilities (PAP) claims that one is only blameworthy for actions which one was able to avoid. Much of the discussion about PAP concerns Frankfurt’s counterexamples to it. After fifty years of refined debates, progress might seem hopeless. Yet, we can make headway by asking: “what’s our reason for believing PAP?” The best answer is this: lacking eligible alternatives—alternatives whose cost is not too high to reasonably opt for—is a good excuse. Yet, this principle is subject to straightforward counterexamples, unless it is given an epistemicised reading. And in this latter case, it does not support PAP. So, PAP is unsupported, at least for now.

Is there a sense in which we exercise direct volitional control over our beliefs? Most agree that there is not, but discussions tend to focus on control in forming a belief. The focus here is on sustaining a belief over time in the face of ‘epistemic temptation’ to abandon it. It is argued that we do have a capacity for ‘doxastic self-control’ over time that is partly volitional in nature, and that its exercise is rationally permissible.

Edmund Gettier objects to analysing knowledge as justified true belief (JTB) on the ground that someone can justifiably infer a true conclusion from a justified false premise and hence not know the conclusion's truth, although the conclusion is justified. For instance, someone can justifiably deduce a true p v r from a justified but false p, where he has no justification for the true r. Gettier's objection draws on two assumptions: first, that a justified belief can be false; second, that a premise can justify a conclusion even though the premise is false.

Some JTB advocates grant the first assumption but deny the second. They usually concede the first assumption to protect the respectability of non-deductive inference. The argument is that if evidence e can nondeductively justify the conclusion c, then it must be possible for c to be justified and yet false, since e does not entail c. Although the assumption is sound, the argument as it stands fails to show it. But let us set this point aside for the moment.

This paper develops a moderate pessimist account of moral deference. I argue that while some pessimist explanations of the puzzle of moral deference have been misguided in matters of detail, they nevertheless share an important insight, namely that there is a justified moral agency ideal grounded in pro tanto reasons against moral deference. This thought is unpacked in terms of a set of values associated with the practice of morality. I conclude by suggesting that the solution to the puzzle of moral deference developed here gives us a plausible recipe for generalizing to certain cases of nonmoral deference as well.