波埃修斯在《哲學的安慰》中提出了一個神義論問題：上帝造了萬物並安排了確定的自然秩序但卻唯獨不管人間的善惡。他破解此問題的關鍵之一是借助新柏拉圖主義者波菲利的解釋以及邏輯分析重新解釋亞里斯多德對人的經典定義「人是有理性的動物」。人類與其他萬物的共性是有身體，但與他們的最大差別則是靈魂中的理性。理性就是追求至善的意願和力量，是內在於人的自然本性的美德，是人之所以為人的本質。人性的脆弱源自其動物性與有限理性自由決斷的矛盾，因為無知、欲望、美德敗壞，有的人會轉向惡的道路，變成非人的存在，即非理性的低等動物。上帝是理性的本原，人是理性屬下的一種動物。將人性的重點從動物轉換為靈魂的理性，他論證了人性本質是善的，惡是人有限理性的自由決斷造成的，而不是上帝所造的。

In The Consolation of Philosophy, Boethius raises the problem of theodicy: God created all things and rules the nature with the definite order but does not care about good and evil among human beings. The key to his solution was a reinterpretation of Aristotle’s classic definition of human “as a rational animal” withe the interpretations of the neo-Platonist Porphyry and logical analysis. Human species have a body in common with all other creatures, but the major difference with them is the reason (rationality) of the mind. Reason is the will and power to pursue the highest good, the virtue that is inherent in human nature, the essence that makes one to be human. The frailty of human nature is implied in the contradiction from its animal side and the free will of a limited ration: because of ignorance, desire, and corruption of virtues, some people may turn to the path of evil and become non-human beings, i.e. irrational lower animals. By introducing God as the principle of reason, then human is a species of animal under the genus of reason, and reason is what makes human beings similar to God. It is the exercise of reason that elevates humanity toward divinity, finally to attain the happiness.