Online research in philosophy

This paper contains replies to comments on the author's paper "A Priori Knowledge and the Scope of Philosophy." Several points in the argument of that paper are given further clarification: the notion of our standard justificatory procedure, the notion of a basic source of evidence, and the doctrine of modal reliabilism. The reliability of intuition is then defended against Lycan's skepticism and a response is given to Lycan's claim that the scope of a priori knowledge does not include philosophically central topics such as the nature of consciousness. Next a counterfactual account of intuitions proposed by Sosa is criticized. Finally, in response to certain questions raised by Sosa, the explanation of the evidential status of intuition offered in the original paper receives further elaboration.

For scientific essentialists, the only logical possibilities of existence are the real (or metaphysical) ones, and such possibilities, they say, are relative to worlds. They are not a priori, and they cannot just be invented. Rather, they are discoverable only by the a posteriori methods of science. There are, however, many philosophers who think that real possibilities are knowable a priori, or that they can just be invented. Marc Lange [Lange 2004] thinks that they can be invented, and tries to use his inventions to argue that the essentialist theory of counterfactual conditionals developed in Scientific Essentialism [Ellis 2001, hereafter SE] is flawed.

In this paper I argue that aim-oriented empiricism provides decisive grounds for accepting scientific realism and rejecting instrumentalism. But it goes further than this. Aim-oriented empiricism implies that physicalism is a central part of current (conjectural) scientific knowledge. Furthermore, we can and need, I argue, to interpret fundamental physical theories as attributing necessitating physical properties to fundamental physical entities.

Jonathan Weinberg (2007) has argued that we should not appeal to intuition as evidence because it cannot be externally corroborated. This paper argues for the normative claim that Weinberg’s demand for external corroboration is misguided. The idea is that Weinberg goes wrong in treating philosophical appeal to intuition analogous to the appeal to evidence in the sciences. Traditional practice is defended against Weinberg’s critique with the argument that some intuitions are true simply in virtue of being intuited by the majority of people. The argument proceeds by way of examining a paradigm case, Putnam’s Twin Earth.

The topic of a priori knowledge is approached through the theory of evidence. A shortcoming in traditional formulations of moderate rationalism and moderate empiricism is that they fail to explain why rational intuition and phenomenal experience count as basic sources of evidence. This explanatory gap is filled by modal reliabilism -- the theory that there is a qualified modal tie between basic sources of evidence and the truth. This tie to the truth is then explained by the theory of concept possession: this tie is a consequence of what, by definition, it is to possess (i.e., to understand) one’s concepts. A corollary of the overall account is that the a priori disciplines (logic, mathematics, philosophy) can be largely autonomous from the empirical sciences.

The counterintuitive implications of law necessitarianism pose a far more serious threat than its proponents recognize. Law necessitarians are committed to scientific essentialism, the thesis that there are metaphysically necessary truths which can be known only a posteriori. The most frequently cited arguments for this position rely on modal intuitions. Rejection of intuition thus threatens to undermine it. I consider ways in which law necessitarians might try to defend scientific essentialism without invoking intuition. I then consider ways in which law necessitarians who accept the general reliability of intuition might try to explain away the intuitions which conflict with their theory.

Scientific essentialism holds that: (1) each scientific kind is associated with the same set of properties in every possible world; and (2) every individual member of a scientific kind belongs to that kind in every possible world in which it exists. Recently, Ellis (Scientific essentialism, 2001 ; The philosophy of nature 2002 ) has provided the most sustained defense of scientific essentialism, though he does not clearly distinguish these two claims. In this paper, I argue that both claims face a number of formidable difficulties. The necessities of scientific essentialism are not adequately distinguished from semantic necessities, they have not been shown to be necessities in the strictest sense, they must be relativized to context, and they must either be confined to a subset of scientific properties without warrant or their connection to causal powers must be revoked. Moreover, upon closer examination (1) turns out to be a trivial thesis that can be satisfied by non-kinds, and (2) is inapplicable to some of the most fundamental kinds in the basic sciences.

This paper provides a defense of two traditional theses: the Autonomy of Philosophy and the Authority of Philosophy. The first step is a defense of the evidential status of intuitions (intellectual seemings). Rival views (such as radical empiricism), which reject the evidential status of intuitions, are shown to be epistemically self-defeating. It is then argued that the only way to explain the evidential status of intuitions is to invoke modal reliabilism. This theory requires that intuitions have a certain qualified modal tie to the truth. This result is then used as the basis of the defense of the Autonomy and Authority theses. The paper closes with a defense of the two theses against a potential threat from scientific essentialism.

It is argued that, because of scientific essentialism, two currently popular arguments against the mind-body identity thesis -- the multiple-realizability argument and the Nagel-Jackson knowledge argument -- are unsatisfactory as they stand and that their problems are incurable. It is then argued that a refutation of the identity thesis in its full generality can be achieved by weaving together two traditional Cartesian arguments -- the modal argument and the certainty argument. This argument establishes, not just the falsity of the identity thesis, but also the metaphysical possibility of disembodiment.