Problem
In Ch. 1 of The World or Treatise on Light, Descartes attempts to introduce a distinction between the qualities of our sensations (smells, tastes, sounds, feelings of warmth, hardness and softness, color) and the qualities of the objects which produce those sensations. In order to help illustrate this distinction, Descartes says that the difference between sensations and the objects that produce them is analogous to the difference between words and the things they signify. Explain how this analogy is supposed to work. In particular, in what way are sensations supposed to be different from the material objects which produce them?