Buddhi means intelligence; one has to be intelligent if he wants to enjoy. Animals do not have really developed intelligence and so cannot enjoy life as a human being can. The hands, the nose, the eyes, the other sense organs, and all the bodily parts may be present on a dead man, but he cannot enjoy. Why not? The enjoying energy, the spiritual spark, has left, and therefore the body has no power. If one looks further into the matter with a little intelligence, he can understand that it was not the body that was enjoying at all but the small spiritual spark that was within. Although one may think that he is enjoying by the bodily sense organs, the real enjoyer is that spiritual spark.