 Galen believed each part of this tripartite soul controlled specific functions within the body and that the soul, as a whole, contributed to the health of the body, strengthening the "natural functioning capacity of the organ or organs in question".The rational soul controlled higher level cognitive functioning in an organism, for example, making choices or perceiving the world and sending those signals to the brain.He also listed "imagination, memory, recollection, knowledge, thought, consideration, voluntary motion and sensation" as being found within the rational soul.