To: Gordon F.
From: Geoffrey Klempner
Subject: Tracing a path from the mental to the physical
Date: 4 April 2007 08:49

Dear Gordon,

Thank you for email of 28 March, with your second essay for the Philosophy of Mind program, in response to the question, 'Whereas one could trace a path from the Morning Star to the Evening Star, or from the North side of Everest to the South side, there is no path one could trace from the inside of the mind to the outside.' - Discuss.

What is a 'path'? Good question. Here's an extract from an astronomy site:

'The ancient Greeks popularly identified a morning star, Phosphorus, and an evening star, Hesperus; both would appear periodically in the morning or evening sky, respectively, and both were extremely bright (brighter than anything else in the sky, other than the Sun and the Moon).

'Greek astronomers observed these "stars" to appear and disappear from the twilight skies periodically, but both could never be seen at the same time of year. They correctly identified these objects not as two stars, but rather as a single planet, which we know today as Venus.

'As Earth and Venus orbit the Sun, all three bodies constantly change positions relative to each other, causing Venus to appear alternately to the east or the west of the Sun; alternately in the early evening or early morning skies.'

(http://chabotspace.org/vsc/talk/astronomyFAQs.asp?selected=5)

In hypothesising that Hesperus is Phosphorus, the Ancient Greeks did not trace or follow a path, because they did not have the means to do this. What they imagined, or conceived, is that it would be possible (if one could rise sufficiently high above the surface of the Earth) to keep 'Hesperus' constantly in view until it became 'Phosphorus'. So the path would be a path in time. Whereas the path between the North and South side of Everest is a path through space.

Of course, we are dealing with a metaphor. I fully take Lakoff and Johnson's point that most of our conceptual vocabulary has a metaphorical element. The question to ask is how the 'path' metaphor is functioning in these examples of empirically discovered identities.

The fundamental idea is Frege's claim in 'Sense and Reference' that empirical statements of identity involve different 'modes of presentation'. An object is 'given' in different ways and when an identity is empirically discovered what happens is that we succeed in connecting two modes of presentation together. Frege took his notion of modes of presentation from geometry and number theory. The arithmetical statement, 366x21 = 193x42 is informative because the same number is identified by two different pairs of values of the times-function.

The target of the claim stated in the question is materialism of the 'contingent identity thesis' variety, as proposed by the Australian materialists Armstrong and Smart (and criticized by Saul Kripke in his book, originally an article, 'Naming and Necessity' - it is interesting to compare Kripke's argument). By contrast with the radical questioning of the 'inner/outer' distinction which I am attempting in these units, and which I am glad to see is echoed in the article by Johnson and Rohrer which you quote from, the Australian materialists are happy to put forward the identity thesis as an empirical claim, in the spirit of Occam's razor. Given the absence of sufficient evidence to the contrary, the materialist philosopher - or the neuroscientist - hypothesises that, e.g. pain IS stimulation of C-fibres.

The problem with this is that the Australian philosophers have not succeeded in explaining the meaning of such an identity claim. The term 'identity' is just not doing any work here, and this is demonstrated (as I would put it) by the lack of a 'path' between the inside and outside of the human subject, conceived as such. There is nothing that would count as identifying one and the same entity as, from one 'side', pain and from the other 'side', stimulated C-fibres. Another way of putting this would be to say that without any loss of meaning one could substitute 'lawlike correlation' for 'identity'.

You say, 'it may or may not be that the arguments of Johnson and Rohrer establish a convincing refutation of any Cartesian-type mind-body dichotomy only because they have used body-based reasoning.' But this gets things the wrong way round. It is the Cartesian who has embraced the spatial metaphor of 'inside' and 'outside'. The Australian 'materialists' are, in reality, unreformed Cartesians who think that they have found an easy escape route from dualism.

Of course, that is not to say that there could not be a form of mind-body dualism which succeeds in eschewing the spatial metaphor altogether. That WOULD be interesting. I have no idea what form such a dualism would take.

There is a picture (which turns out to be just another metaphor) of philosophers as striving with all their might to be literal and avoid all metaphor, always seeking to employ words in their 'correct' unmetaphorical sense. You sometimes get this impression from accounts of the aims and methods of philosophical analysis. The classic example would be Rudolph Carnap. My own view is that it is perfectly safe and indeed necessary for philosophers to employ the rich and variegated palette of meanings available to all of us - impregnated as they are with metaphors and resonances which cannot be fully traced out - and not confine themselves to a narrow range of pure colours.

All the best,

Geoffrey