René Descartes claimed that his mind or soul feels “passions,” or sensations and pains, in the body. The soul is therefore connected to all parts of body, although there is one part of the brain, namely the pineal gland, “where it exercises its functions more particularly than elsewhere.” That is, the soul directly affects the body through the pineal gland by setting animal spirits in motion, via the will. (Descartes thought that the will was infinite because it was a copy of God’s will, but that human understanding is limited. Because the will often outstrips the understanding, all manner of human evils and misfortunes follow.) Consciousness, or the representation in the mind of the sensation and pains in the body, was unique to human beings, according to Descartes. He thought that animals lacked both a pineal gland and consciousness, and were therefore mere machines.