What does the word cat mean? This course looks at three answers. One says that cat is just the set of all cats. Another says that cat refers to a prototypical cat, one described by the characteristics common to all the cats that you have ever seen. The third answer says that cat is the word that the brain associates with the cats that you saw when you were younger. Each of these answers assumes that the mind works in a certain way, so the right one tells us something about how the mind works in situations that have nothing to do with the meaning of cat.