多瑪斯人學的形上基礎

人的完整統一性及靈魂不朽是中世紀時期人學最為困擾，也是爭議最多的兩個問題。哲學家以二元論及普遍形質論來解釋人的完整性。如此二元論的人學思想以不同的方式成為中世紀時期主流的人學思想。多瑪斯反對任何形式的二元論，他為人學尋找形上的統一基礎。為多瑪斯，人的完整統一性要求實體形式的統一性，靈魂是人的實體形式及在自身的實體。唯人的靈魂是受造的，它的存有是分享自存有本身（Ipsumesse）。理性靈魂的本性是精神的，它是人的本質，唯非人的完整的種（species）。精神的靈魂被賦予存有，它是自立的實體，但不在自身分開地存在，理性的精神靈魂以其存有統一人的靈魂與身體，如此人具有完整的統一性。存有為現實，是統一性的基礎，它具絕對的優先性。多瑪斯的存有為現實的概念超越亞理斯多德形式為現實的概念，如此他為精神的理性奠定形上基礎。故在人的本體結構上有雙重的潛能與現實的組合；在形上層次是存有－現實與本質－潛能的組合。在物理層次是靈魂－形式（現實）與身體－質料（潛能）的組合。但理性靈魂因是自立的實體，它是內在地獨立於身體。理性靈魂因其有存有，具不朽的形上條件。

關鍵字

多瑪斯；靈魂；實體；身體；存有的現實

並列摘要

During the Middle Ages, the two problems which philosophers concern the most are the holistic unity of man and the immortality of soul. In order to explain these basic Christian beliefs, philosophers adopt the dualism and universal hylomorphism. The reason to take such a stance is to ensure the immortality of soul.For Aquinas, the human rational soul is both the substantial form of body and the substance in its own right, and the holistic unity of man requires the unity of the substantial form. Since the rational soul is created by God, its esse (being) participates in Ipsum Esse. Rational soul is the essence of humans, but not its complete species. It needs to be united with a body. It is spiritual by nature. Once the rational soul is created, it has being, it is a subsistent substance, but not exists separately by itself. The being of the rational soul then unites the composit man's soul and body. Being is the unifying principle. It has absolute priority. There are double composition of potency and act in man's ontological structure. On metaphysical level, the composition of being-act (or actus essendi) and essence-potency. On physical level, the soul (act-form) and body (potency-matter), yet the rational soul is essentially independent from body. The being of the rational soul is its metaphysical foundation of immortality.