Howard Robinson

Thought experiments are usually employed by philosophers as a tool in conceptual analysis. We pose ourselves questions such as “Would it be the same F if p?” or “Would it count as knowledge if q,” where p and q state some bizarre circumstances that are unlikely actually to occur and may even be beyond current technical possibility. The answers we are inclined to give to such questions are held to throw light on the nature of our concepts of, in these cases, identity and knowledge. But the facts about our concepts that are unearthed in this way are implicitly assumed to be deep, not superficial, facts. They are not meant to be facts contingent upon our current linguistic usage, psychology, or social structure, where these could easily be otherwise. If they were just facts of this superficial kind, it would hardly be worth the effort of uncovering them, for they would bind no-one who preferred a different convention or practice. The conceptual truths revealed are meant to be unavoidable, in some sense, and not merely conventional: there is something Platonic or Kantian in the background. The argument of Sections 2–8 of this essay is that, in the case of the thought experiments used to throw light on our concepts of person and personal identity, the results do not seem to be deep or hard to revise, and that this is so largely because of the ontological assumptions shared by more or less all participants in the debate. I shall be arguing that it is primarily these ontological assumptions, rather than the insight into our concepts that the thought experiments are supposed to bring, that determine the answers to the questions about persons and their identity. In the final two sections I shall make some cautious qualifications to this conclusion.

This entry concerns dualism in the philosophy of mind. The term ‘dualism’ has a variety of uses in the history of thought. In general, the idea is that, for some particular domain, there are two fundamental kinds or categories of things or principles. In theology, for example a ‘dualist’ is someone who believes that Good and Evil — or God and the Devil — are independent and more or less equal forces in the world. Dualism contrasts with monism, which is the theory that there is only one fundamental kind, category of thing or principle; and, rather less commonly, with pluralism, which is the view that there are many kinds or categories. In the philosophy of mind, dualism is the theory that the mental and the physical — or mind and body or mind and brain — are, in some sense, radically different kinds of thing. Because common sense tells us that there are physical bodies, and because there is intellectual pressure towards producing a unified view of the world, one could say that materialist monism is the ‘default option’. Discussion about dualism, therefore, tends to start from the assumption of the reality of the physical world, and then to consider arguments for why the mind cannot be treated as simply part of that world

This chapter starts by restating the causal-hallucinatory argument against naive realism. This argument depends on the possibility of “philosophers' hallucinations.” It draws attention to the role of what the chapter refers to as the nonarbitrariness of philosophers' hallucinations in supporting this argument. The chapter then discusses three attempts to refute the argument. Two of them, those associated with John McDowell and with Michael Martin, are explicitly forms of disjunctivism. The third, exemplified by Mark Johnston, has, the chapter claims, disjunctivist features. None of these responses to the argument is plausible

I claim that there are four major strands of argument for externalism and set out to discuss three of them. The four are: (A) That referential thoughts are object-dependent. This I do not discuss. (B) That the semantics of natural kind terms is externalist. (C) That all semantic content, even of descriptive terms, stems from the causal relations of representations to the things or properties they designate in the external world. (D) That, because meaning is a social product and no individual can capture the whole social practice that defines a concept, what the speaker means always outruns what he can know.I briefiy discuss (C) and (D) and conclude that they cannot be correct, because, if they were, the content of every thought would permanently transcend the refiective grasp of all thinkers. Then I discuss (B) and conclude that, though Putnam shows something interesting about natural kind terms -- namely that a real verbal definition requires science -- this has none of the consequences for philosophy of mind that it is normally supposed to have

I consider what I hope are increasingly sophisticated versions of ontological argument, beginning from simple definitional forms, through three versions to be found in Anselm, with their recent interpretations by Malcolm, Plantinga, Klima and Lowe. I try to show why none of these work by investigating both the different senses of necessary existence and the conditions under which logically necessary existence can be brought to bear. Although none of these arguments work, I think that they lead to interesting reflections on the nature of definition, on the conditions for possessing the property of necessary existence and point towards a different, neo-Platonic ground for God’s meeting the criteria for being logically necessary.