Medieval Philosophy

Having devoted extensive attention to the development of philosophy among the ancient Greeks, we'll now cover more than a millenium of Western thought more briefly. The very name "medieval" (literally, "the in-between time") philosophy suggests the tendency of modern thinkers to skip rather directly from Aristotle to the Renaissance. What seemed to justify that attitude was the tendency of philosophers during this period to seek orthodoxy as well as truth.

Nearly all of the medieval thinkers—Jewish, Christian, and Muslim—were pre-occupied with some version of the attempt to synthesis philosophy with religion. Early on, the neoplatonism philosophy of Plotinus seemed to provide the most convenient intellectual support for religious doctrine. But later in the medieval era, thanks especially to the work of the Arabic-language thinkers, Aristotle's metaphysics gained a wider acceptance. In every case, the goal was to provide a respectable philosophical foundation for theological positions. Augustine: Christian Platonism

The first truly great medieval philosopher was Augustine of Hippo, a North African rhetorician and devotee of Manichaeanism who converted to Christianity under the influence of Ambrose and devoted his career to the exposition of a philosophical system that employed neoplatonic elements in support of Christian orthodoxy. The keynote of Augustine's method is "Credo ut intellegiam" ("I believe in order that I may understand"), the notion that human reason in general and philosophy in particular are useful only to those who already have faith.

Thus, for example, Augustine simply rejected the epistemological criticisms mounted by the Academic skeptics. Even if it were true that I am mistaken about nearly everything that I suppose to be true, he argued, one inescapable truth will remain: "Si fallor, sum" ("If I am mistaken, I exist"). [This doctrine is an interesting anticipation of Descartes's later attempt to establish knowledge on the phrase "Cogito ergo sum".] Upon this foundation, Augustine believed it possible to employ human faculties of sense and reason effectively in the pursuit of substantive knowledge of the world.

Human Life

Although Augustine was significantly influenced by the moral philosophy of Cicero, he generally argued that the Stoics were excessively optimistic in their assessment of human nature. One of Augustine's central contributions to the development of Christian theology was his heavy emphasis on the reality of human evil. If, as Augustine certainly believed, the world and everything in it is the creation of a perfectly good god, then how can the human beings who constitute so prominent a part of that creation be inherently evil? Like Plato and Plotinus, but unlike the Manichaeans, Augustine now argued that evil is not anything real, but rather is merely the absence of good. Augustine held that the classical attempts to achieve virtue by discipline, training, and reason are all boud to fail. Thus, the redemptive action of god's grace alone offers hope. Again using his own life as an example, Augustine maintained that we can do nothing but wait for god to work with us in the production of a worthwhile life. (Our happiness never enters into the picture.)

God's Existence

That there is indeed a god, Augustine proved in fine Platonic fashion: Begin with the fact that we are capable of achieving mathematical knowledge, and remember that, as Plato demonstrated, this awareness transcends the sensory realm of appearances entirely. Our knowledge of eternal mathematical truths thus establishes the immateriality and immortality of our own rational souls. (So far, the argument is straight out of Plato's Phaedo.)

Augustine further argued that the eternal existence of numbers and of the mathematical relations that obtain among them requires some additional metaphysical support. We can still balance our checkbooks with confidence because, of course, god invariably wills eternally. But in principle, Augustine held that even necessary truths are actually contingent upon the exercise of the divine will.

Human Freedom

This emphasis on the infinite power of god's will raises a significant question about our own capacity to will and to act freely. If, as Augustine supposed, god has infinite power and knowledge of every sort, then god can cause me to act in particular ways simply by willing that I do so, and in every case god knows in advance in what way I will act, long before I even contemplate doing so. Augustine's answer to this predicament lies in his analysis of time. A god who is eternal must stand wholly outside the realm of time as we know it, and since god is infinitely more real than we are, it follows that time itself does not exist at the level of the infinitely real. The passage of time, the directionality of knowledge, and all temporal relations are therefore nothing more than features of our limited minds. And it is within these limitations, Augustine supposed, that we feel free, act on our volitions, and are responsible for what we do. God's foreknowledge, grounded outside the temporal order, has no bearing on the temporal nature of our moral responsibility. Once again, a true understanding of the divine plan behind creation resolves every apparent conflict.