Send me one idea for our discussion of Clark and Chalmers before 8 am Mon. As with other such assignments, it’s enough to send me a few words indicating a topic, but please include a specific page reference.
This article raises the question of the extent to which you mind is confined to your body. I suspect it will be easiest to approach that by way of the examples in §§2 and 4, but §§3 and 5 may be helpful for thinking about those examples—and for thinking of others.
Putnam’s Twin Earth example. On p. 9, the authors allude to an example that they assume will be known to their readers. Here is Putnam’s original description of the example:
We shall suppose that somewhere there is a planet we shall call Twin Earth. Twin Earth is very much like Earth: in fact, people on Twin Earth even speak English. In fact, apart from the differences we shall specify in our science-fiction examples, the reader may suppose that Twin Earth is exactly like Earth.…
Although some of the people on Twin Earth … speak English, there are, not surprisingly, a few tiny differences between the dialects of English spoken on Twin Earth and standard English.
One of the peculiarities of Twin Earth is that the liquid called “water” is not H2O but a different liquid whose chemical formula is very long and complicated. I shall abbreviate this chemical formula simply as XYZ. I shall suppose that XYZ is indistinguishable from water at normal temperatures and pressures. Also, I shall suppose that the oceans and lakes and seas of Twin Earth contain XYZ and not water, that it rains XYZ on Twin Earth and not water, etc.
Hilary Putnam, “Meaning and Reference,” The Journal of Philosophy, vol. 70 (1973), pp. 699-711 (on JSTOR at 2025079)
He goes on to note that Earthlings visiting Twin Earth would report back, “On Twin Earth the word ‘water’ means XYZ,” and argues that this means that meanings are not “in the head” (since what is in the head would not have differed from Earth to Twin Earth before the chemical composition of the stuff called ‘water’ was discovered and there is no reason to suppose the meaning of ‘water’ has changed since then). That view about meaning came to be called “externalism.”