Epicurus criticized the notions of the atomists, observing that free will is a “fact of experience”. If the atomic world is totally determined then this free will must either be accounted for by supposing that there is something or other in the “soul” which is not atomic, or else the atoms themselves must be assumed to have the power of “free” movement. Epicurus assumes that the second alternative is the only viable one. (Warner, 1959, p. 150) Free-will is accepted by Epicurus not only because it fits into his theory of atomic spontaneity, but also because it is “less disturbing to man’s peace of mind than blind fate or inexorable necessity.” (Thilly, 1951, p. 125) Epicurus’ first argument bears an infantile resemblance to the modern argument based on the “uncertainty” principal; his second argument still holds emotional appeal.

The Stoics, like Epicurus, postulate a form of freedom, but their “freedom of conformity to rational law is very different from the Epicurean freedom of chance or causal indeterminacy.” (Thilly, 1951, p. 125) According to the Stoics, the universe is in a cycle of death and rebirth, each cycle being an exact replication of the previous cycles. Thus, everything is absolutely determined, even the human will; the universe forms an unbroken causal chain in which nothing happens by chance, but everything follows necessarily from the one first cause or mover. Humankind is free, state the Stoics, in the sense that he can assent to what fate decrees, but, whether he assents or not, he must obey. (Thilly, 1951, pp. 135-136)

At a much later date, Spinoza made a similar point when he compared the human feeling of freedom to a stone’s belief as it is thrown through space that it determines its own trajectory and selects the place and time of its fall. The stone — and each of us — is in fact “free” in its (our) decisions, as long as it (we) desires to follow the trajectory already set for it: its lack of freedom is only appreciated when deviations are attempted. (Durant, 1926, p. 196) In this way, Spinoza appears to have countered the argument for “introspective” verification of freedom. According to the Stoics, and Spinoza (Durant, 1926, p. 196), humans are free in so far as they have logical thought, and cease to be governed by images and impulses, like the brute or animal: these philosophers of differing periods thus seem to converge on the same point to be made by Plato. Is this the solution to the question of determinism and freedom?

The last of the great Greek Philosophers, Plotinus, accepted the concept of free-will, believing that such a concept is necessary if the concept of sin or moral responsibility is to have any meaning. This ethical argument was to become prominent among the church theologians-philosophers of the Middle- Ages and found its most profound expression in the writings of Emanuel Kant. If there is an absolute command to duty (deontological ethic), as Kant proposed, then our wills must be free, for how could we conceive such a notion as duty if we are not free? ((Durant, 1926, p. 302)