Abstract

Through an analysis of a part of Thomas’ arguments on the rational soul’s subsistence, the article exposes the reasons why it is necessary and possible to affirm that the human soul is a substance in its proper sense, even if it does not have the entire human essence when it subsists apart from the body. Thus the article intends to answer a question raised by B.C. Bazán. The analysis is articulated applying the principle nihil agit nisi secundum quod est actu in different ways in order to make explicit the reason why the soul is the suppositum of intellectual operations and faculties and therefore a substance; then the article reaffirms that the substantial form’s definition is related to the act of being in order to distinguish the “virtual” way in which any substantial form has the entire species, from the “real” way in which any substance has an entire substantial essence.