Despite its relative brevity, On Free Choice of the Will contains almost every distinctive feature of Augustine's philosophy. It presents the essentials of his ethics, his theory of knowledge, and his views of God and human nature. It is therefore the ideal introduction to Augustine's thought for introductory courses and surveys of medieval philosophy, where there is not time for a complete and detailed reading of longer works such as the Confessions and The City of God. But its very richness makes it impossible for me to discuss in this brief introduction even all of the more important aspects of this work. In what follows, therefore, I concern myself chiefly with the two concepts that figure in the title: freedom and the will.
The word 'freedom' has many senses. One sort of freedom involves the absence of restraints. As long as the door is not locked, I am free (in this sense) to leave the room. We might call this physical freedom. Physical freedom means that there is nothing to hinder me from acting as I choose to act.
But suppose I live in a deterministic universe. Every choice I make is determined by prior states of the universe, states over which I have no control. I may still be physically free--no one has locked me up or tied me down--but it seems that I lack freedom in some stronger and more interesting sense. I am free to act as I choose, but my choices themselves are not free. The freedom to choose in a way that is not determined by anything outside my control is what I shall call metaphysical freedom.
The view that human beings have metaphysical freedom is called 'libertarianism'. Libertarianism is no longer a popular view among philosophers, most of whom think that at best we have only physical freedom. But Augustine was one of the great defenders of libertarianism; indeed, he was the first to articulate the view clearly. According to Augustine, human beings are endowed with a power that he calls the will. Augustine compares the will to the weight of an inanimate object. Just as a falling apple is carried to the ground by its weight, so a human being is carried to his goal (whatever that may be) by his will. But the analogy is deficient in one important respect. The falling apple has no say about where its weight will take it. A human being,