It may be news to many of you that Origen, the church father, and Plotinus, the great Neoplatonist philosopher, at one time or another, both sat under the teaching of Ammonius Saccas, who was perhaps the founding teacher of Neoplatonism. Joseph Trigg, in his book on Origen, briefly explains the similarities and differences between Origen and Plotinus on astrology. Their differences are presumably due to Origen’s Christian devotion to the biblical text as the sole source of prophecy in the cosmos:

[Origen] endeavors to show that knowledge of future events does not imply causation. This applies, in particular, to God’s total knowledge from the perspective of eternity. Origen found the Scriptural description of the stars as “signs” to be congruent with the use of the same terminology by Platonic philosophers. His argument is sufficiently close to that of Plotinus in Enneads 3.1, 5–6 and 2.3 that we must assume a common source, most likely their common teacher, Ammonius Saccas. Plotinus also argued that the stars are signs (sêmeia) and criticizes astrology for implying that the stars are evil or capricious, but, while denying that they determine our character, he allows that the stars may exercise some influence. The stars are like letters in which those who know how to read this sort of writing can ascertain future events, “discovering what is indicated (sêmainomenon) by analogy,” but the stars do not cause these events. Using the terminology of the apocryphal Prayer of Joseph, Origen readily admits, by virtue of the analogy between Scripture and the cosmos, that the stars are “the tablet of heaven” which the angelic powers can read. In fact, they receive instruction from God by reading stars much as we do by reading the Bible. Nonetheless, Origen argues, for logical and scientific reasons, that we, as human beings, cannot predict the future by means of horoscopes. ¹