Rick Ritchie gives a brief summary on the importance of Plato’s thought in Christianity
“The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.” — Alfred North Whitehead
Hard questions always arise when Christianity confronts worldly philosophy. What could a philosopher offer us that is not offered better in our revelation? As Tertullian asked, “What hath Athens to do with Jerusalem?” Still, certain thinkers of the past were so influential that they could only be ignored for so long. While some of our apologists countered them, many were also trained in their schools, incorporating their techniques and sometimes importing their doctrines into their own theological systems. This is especially true of the key Greek philosophers Plato and Aristotle. Most of us know that for a period in the Middle Ages, the teachings of Plato’s student Aristotle were broadly accepted through the teaching of Thomas Aquinas in the Summa Theologica and even contributed to the philosophical basis of dogmas such as Transubstantiation. Was Plato ever so highly regarded? And should he have been?
The Platonic influence in theology tends to be very general. While a system of specific philosophical categories was adopted from Aristotle, and his virtue theory was adapted to fit Catholic teachings, Plato’s influence on the East was usually more an overall stance regarding the nature of the world than an adoption of specific doctrines. Perhaps Plato’s most overarching influence on theology is famously taught in his analogy of the cave from Book 7 of the Republic. According to this, the world we see is conceived as shadows projected against a cave wall. These shadows are merely suggestive of the ideal (and thus real) archetypes that cast them. Plato’s theory of the forms comes from this. We see chairs about us, but these are mere shadows of the perfect idea of the chair in the realm of the invisible forms in which they participate, the perfect form of the chair. It is a short move from this concept to certain ways of conceiving of heaven and earth and even forming a hierarchy of “being” from earth up to heaven.
Some specific doctrines related to the preexistence of the soul and the final triumph of the good have also been traced from Plato to the church father Origen, though Origen tended to be textual in his arguments, and this connection is tenuous—as Platonic influence often can be!
Plato’s biggest impact on the Church was probably made through Augustine by means of Neoplatonism. This version of Platonism tended to emphasize the superiority of the soul to the body and the personal ascent from the earthly to the heavenly through contemplation, as things of the physical realm are left behind. This goal of personal and direct apprehension of the divine is known as mysticism. The Confessions contain accounts of two such ascents, an earlier Neoplatonist-influenced version and a later one preceding the death of his mother, an ascent which could be argued to be more Christian in nature, but which still featured contemplation as the route to God. As with many church fathers, while some passages show admixture with foreign elements, elsewhere, the influence seems lighter or absent.
Through Augustine, Neoplatonism probably also impacted Lutheranism, though not so much in individual doctrines. In the philosophical theses at the end of the “Heidelberg Disputation,” Luther registers his own estimate of the comparative worth of Plato and Aristotle by saying, “Aristotle wrongly finds fault with and derides the ideas of Plato, which are actually better than his own.” Luther’s Works, volume 31, p. 42. While this is no wholescale endorsement of Plato and may have been said more to run down Aristotle than elevate Plato, it hints at favoring a cast of mind focused on the whole rather than the parts. Aristotle would have us believe in a God aloof from the world, creating it but standing wholly apart. Plato would have us believe that everything we see expresses a higher reality. So would Luther, even if the significance was hidden.
Platonism encourages a mode of thinking that clashes most harshly with Luther's Gospel. Plato teaches us that all real knowledge is already in us by nature and merely needs to be drawn out of us. This goes against the very idea of the Gospel as "good news" that comes from outside of us. Good news of things that happened in the mess of history, a history that might have gone another way except for the intervention of God. Good news that runs contrary to what we find when we look inside and find a mess that matches the turbulence we find in the day's wars and tumults. We cannot look inside ourselves and predict the divine rescue. We need for someone to enter the cave with us, and lead us out into the daylight.