Only a living entity can have goals or can originate them. And it is only a living organism that has the capacity for self-generated, goal-directed action. On the physical level, the functions of all living organisms, from the simplest to the most complex — from the nutritive function in the single cell of an amoeba to the blood circulation in the body of a man — are actions generated by the organism itself and directed to a single goal: the maintenance of the organism’s life.
When applied to physical phenomena, such as the automatic functions of an organism, the term “goal-directed” is not to be taken to mean “purposive” (a concept applicable only to the actions of a consciousness) and is not to imply the existence of any teleological principle operating in insentient nature. I use the term “goal-directed,” in this context, to designate the fact that the automatic functions of living organisms are actions whose nature is such that they result in the preservation of an organism’s life.