The sense of thinking

  It will be found that the great majority, given the premiss that thought is not distinct from corporeal motion, take a much more rational line and maintain that thought is the same in the brutes as in us, since they observe all sorts of corporeal motions in them, just as in us. And they will add that the difference, which is merely one of degree, does not imply any essential difference; from this they will be quite justified in concluding that, although there may be a smaller degree of reason in the beasts than there is in us, the beasts possess minds which are of exactly the same type as ours. (Descartes 1642: 288–289.)