Abstract
This paper studies the notion of self-knowledge in Aristotle and principally in Aquinas. According to Aristotle, sensitive operations like seeing or hearing can be perceived by the knower (sensitive consciousness), while there can be also an understanding of the understanding, mainly attributed to God, but not exclusively. In his ethical writings, Aristotle acknowledges the human capacity of understanding and perceiving one’s life and existence, extended also to other persons in the case of friendship. Aquinas receives this heritage and includes also the habitual self-awareness of the mind which was held by Augustine. A more ontological view is taken from the Neoplatonic notion of complete reflexivity of the intellectual soul upon its own essence as a manifestation of total immateriality and self-possession, which is a higher way of existing and living. Thus, the modern idea of self-consciousness is not absent in the Thomistic account of self-understanding, though the term “conscience” was reserved to the moral judgment upon one’s actions as right or wrong. The Thomistic distinction between habitual existential self-knowledge, which is an intellectual experience including perception and judgment, and scientific and abstract human self-knowledge, is useful and provides insight to the ontological value of existential self-knowledge. The last part of the paper argues that according to Aquinas there is a deep connection between self-knowledge and self-love, provided they are rooted on truth and virtue. This point has many consequence in the notion of shared self-awareness and mutual joy in friendship. The author concludes as well that a genuine self-understanding is possible only in friendship based upon virtue.