In ethics, one must begin by asking: What are values? Why does man need them?
“Value” is that which one acts to gain and/or keep. The concept “value” is not a primary; it presupposes an answer to the question: of value to whom and for what? It presupposes an entity capable of acting to achieve a goal in the face of an alternative. Where no alternative exists, no goals and no values are possible.

There is only one fundamental alternative in the universe: existence or nonexistence—and it pertains to a single class of entities: to living organisms. The existence of inanimate matter is unconditional, the existence of life is not: it depends on a specific course of action. Matter is indestructible, it changes its forms, but it cannot cease to exist. It is only a living organism that faces a constant alternative: the issue of life or death. Life is a process of self-sustaining and self-generated action. If an organism fails in that action, it dies; its chemical elements remain, but its life goes out of existence. It is only the concept of ‘Life’ that makes the concept of ‘Value’ possible. It is only to a living entity that things can be good or evil.

To make this point fully clear, try to imagine an immortal, indestructible robot, an entity which moves and acts, but which cannot be affected by anything, which cannot be changed in any respect, which cannot be damaged, injured or destroyed. Such an entity would not be able to have any values; it would have nothing to gain or to lose; it could not regard anything as for or against it, as serving or threatening its welfare, as fulfilling or frustrating its interests. It could have no interests and no goals.
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.

An organism’s life depends on two factors: the material or fuel which it needs from the outside, from its physical background, and the action of its own body, the action of using that fuel properly. What standard determines what is proper in this context? The standard is the organism’s life, or: that which is required for the organism’s survival.
No choice is open to an organism in this issue: that which is required for its survival is determined by its nature, by the kind of entity it is. Many variations, many forms of adaptation to its background are possible to an organism, including the possibility of existing for a while in a crippled, disabled or diseased condition, but the fundamental alternative of its existence remains the same: if an organism fails in the basic functions required by its nature—if an amoeba’s protoplasm stops assimilating food, or if a man’s heart stops beating—the organism dies. In a fundamental sense, stillness is the antithesis of life. Life can be kept in existence only by a constant process of self-sustaining action. The goal of that action, the ultimate value which, to be kept, must be gained through its every moment, is the organism’s life.

An ultimate value is that final goal or end to which all lesser goals are the means—and it sets the standard by which all lesser goals are evaluated. An organism’s life is its standard of value: that which furthers its life is the good, that which threatens it is the evil.

Without an ultimate goal or end, there can be no lesser goals or means: a series of means going off into an infinite progression toward a nonexistent end is a metaphysical and epistemological impossibility. It is only an ultimate goal, an end in itself, that makes the existence of values possible.

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.

Metaphysically, life is the only phenomenon that is an end in itself: a value gained and kept by a constant process of action. Epistemologically, the concept of “value” is genetically dependent upon and derived from the antecedent concept of “life.” To speak of “value” as apart from “life” is worse than a contradiction in terms. “It is only the concept of ‘Life’ that makes the concept of ‘Value’ possible.”

In answer to those philosophers who claim that no relation can be established between ultimate ends or values and the facts of reality, let me stress that the fact that living entities exist and function necessitates the existence of values and of an ultimate value which for any given living entity is its own life. Thus the validation of value judgments is to be achieved by reference to the facts of reality. The fact that a living entity is, determines what it ought to do. So much for the issue of the relation between “is” and “ought.”"

-- Ayn Rand, The Virtue of Selfishness