The end of Greek philosophy is a state in which philosophy has become religion, and religion mystical philosophy. When now many philosophers became Christians, they could use a philosophy which was already half religious. When you hear about the relationship of philosophy and theology, which is often discussed in these rooms here around, then you must not forget that this is not the kind of philosophy which is taught by empiricists, logical positivists, naturalists, etc., as it is done today. But philosophy in the period of the Bible was in itself a religious attitude. It was not simply a discussing of elements, but it was something which had in itself fundamental decisions which had mystical-religious character. This is the reason why Christianity had to deal with philosophy at that time, not only as a nice pastime for intellectually gifted people to whom we leave that pastime, but it was another religion. The name of this religion was Neo-Platonism. In Neo- Platonism, Platonic ideas and also Stoic and Aristotelian ideas were brought together in a system which was philosophical and religious at the same time. Neo-Platonism and the development towards it, expressed the longing of the ancient world for a new religion. It expressed the dissolution of all special religions and it expressed at the same time the catastrophe of autonomous reason, the impossibility of reason to create by itself a new content of life. Therefore these philosophers became mystics, and as mystics, they tried to create under imperial protection (Julian the Apostate) a new religion (ca. 250). In doing so, they had to clash with Christianity. Now I come to that point where Christianity had not only to do with general philosophical tradition in Greece we discussed this already in the Apologists and in Irenaeus and Tertullian – -but Christianity was the rival religion with a philosophical religion, with a philosophy where the beginning and the end is religious. This is what Neo- Platonism is. With this, and the way in which the great Alexandrian theologians, Clement and Origen, put this into reality and used the philosophical religion of the Neo-Platonists to express Christianity, we will deal more fully next week..

Paul Tillich, A History Of Christian Thought – Table of Contents