Online research in philosophy

Introduction Qualia and causation Do qualia exist? Qualia and cognitive science Qualia and other mental phenomena Knowledge of qualia Are qualia irreducible?

Frank Jackson’s knowledge argument (KA) aims to prove, by means of a thought experiment concerning the hypothetical scientist Mary, that conscious experiences have non-physical properties, called qualia. Mary has complete scientific knowledge of colours and colour vision without having had any colour experience. The central intuition in the KA is that, by seeing colours, Mary will learn what it is like to have colour experiences. Therefore, her scientific knowledge is incomplete, and conscious experiences have qualia. In this paper I consider an objection to the KA raised by Daniel Dennett. He maintains that the KA is vitiated by Jackson’s account of Mary’s scientific knowledge. While endorsing this criticism, I will defend the plausibility and relevance of the type of strategy involved in the KA by offering an account of Mary’s scientific knowledge. This account involves formulating a reasonable and not immediately false version of the physicalist thesis with regard to colour experiences. Whether this version of the KA is successful against this type of physicalism is not investigated here.

Frank Jackson argued, in an astronomically frequently cited paper on 'Epiphenomenal qualia'[Jackson 1982 that materialism must be mistaken. His argument is called the knowledge argument. Over the years since he published that paper, he gradually came to the conviction that the conclusion of the knowledge argument must be mistaken. Yet he long remained totally unconvinced by any of the very numerous published attempts to explain where his knowledge argument had gone astray. Eventually, Jackson did publish a diagnosis of the reasons why, he now thinks, his knowledge argument against materialism fails to prove the falsity of materialism [Jackson 2005. He argues that you can block the knowledge argument against materialism - but only if you tie yourself to a dubious doctrine called representationalism. We argue that the knowledge argument fails as a refutation of either representational or nonrepresentational materialism. It does, however, furnish both materialists and dualists with a successful argument for the existence of distinctively first-person modes of acquaintance with mental states. Jackson's argument does not refute materialism: but it does bring to the surface significant features of thought and experience, which many dualists have sensed, and most materialists have missed.

The arguments presented in this comprehensive collection have important implications for the philosophy of mind and the study of consciousness.

Frank Jackson has abandoned his famous knowledge argument, and has explained why in a brief "Postscript on Qualia" (1998). This explanation consists of a direct argument, and an attempt to explain away the intuition that lies at the heart of the knowledge argument. The direct argument is clarified and found to be subtly question-begging. The attempt to explain away the key intuition is reviewed and found to be inadequate. False memory traces, which Jackson mentions at the beginning of the direct argument, are discussed and found not to materially affect the force of the knowledge argument.

Frank Jackson's knowledge argument against physicalism has caused an extensive debate. In this paper, I sketch and examine a new argument against Jackson's view, an argument which appears to retain more of physicalism than other replies to Jackson. this argument draws strength from a causal theory of knowledge, and hold that there is no knowledge of epiphenomenal qualia, hence that Jackson's main conclusions from the thought experiment are incorrect. There are still problems with this argument, however, so the question remains how much of the mental that can be accounted for in physicalist terms.

I argue that Frank Jackson's knowledge argument cannot succeed in showing that qualia are epiphenomenal. The reason for this is that there is, given the structure of the argument, an irreconcilable tension between his support for the claim that qualia are non-physical and his conclusion that they are epiphenomenal. The source of the tension is that his argument for the non-physical character of qualia is plausible only on the assumption that they have causal efficacy, while his argument for the epiphenomenal character of qualia is plausible only on the assumption that they are non-physical. Since these two arguments cannot be combined coherently, the most Jackson's argument can establish is that qualia are non-physical.