Frank Jackson – Leibniz's Law and the Philosophy of Mind

Event Date: 14 May 2012
Senate House
University of London
London WC1E 7HU

Professor Frank Jackson (Princeton University) – Leibniz’s Law and the Philosophy of Mind

We draw some metaphysical conclusions about colour and belief from some epistemological commonplaces. It turns out that this requires us to challenge orthodoxy on the causal efficacy of mental properties and to rewrite the standard argument against dualism, but in a way which is good news for functionalists about the mind.
Under what conditions is P evidence for Q? A comprehensive answer to that question is hard and inevitably controversial. We can however say three things that are, it seems to me, uncontroversial. Whether or not P is evidence for Q depends on i) what Pis, ii) what Q is, and iii) the background evidence. The details of how one might enlarge on these three observations will inevitably be controversial but the basic thought behind each is close to a truism.
The essay is about how to deploy these observations, along with some equally commonsensical observations about when we are entitled to believe that one or another property is instantiated, to reach conclusions in the philosophy of mind on subjects that have been much debated. You might describe this essay as an exercise in using the noncontroversial to adjudicate the controversial. I expect that it will, in its turn, be controversial.
Much of the argumentation will employ Leibniz’s law in epistemic contexts. I know from experience that this worries people. We all know that epistemic contexts are opaque. This, perhaps understandably, suggests that using Leibniz’s law in epistemic contexts involves a fallacy of the famous masked man variety. This means it is sensible (essential?) to take a moment to review why it is fine to use Leibniz’s law in epistemic contexts. Our review will be conducted as a short commentary on an issue that Quine most especially put on the table many years ago, in for example (1966).

Frank Jackson is a regular visiting professor at Princeton University and holds fractional research positions at The Australian National University and La Trobe University. He is a Corresponding Fellow of The British Academy. His publications include: Perception (Cambridge UP 1977), Conditionals (Blackwell1987), The Philosophy of Mind and Cognition, co-authored with David Braddon-Mitchell (Blackwell, 1996), From Metaphysics to Ethics (Oxford UP 1998), Language, Names, and Information (Wiley-Blackwell, 2010). Professor Jackson has held a number of visiting positions, most recently as Leverhulme Visiting Professor at Cambridge University in 2011.

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