Even if he didn’t write a strictly anthropologic work, the man problem is present very much in Tomas de Aquino writings. For him, the man never was in the state of pure nature, because he always depends on the historical situation of his life. Starting from the substance doctrine of Aristotle, Tomas underlines that the man is composed of two elements: body, as material and soul, as form; between these two elements there is always an intimate, substantial unity. The activity that makes different the man from other body beings is knowledge. Getting the faculty of intellect, the man has not only a sensitive knowledge, but, also, the knowledge possibility at intellectual level: thus, it can achieve the truth, understood as conformity between intellect and known object.