In this text, of which we have translated a large excerpt, Olivi defends his own version of the identity theory of the soul and its powers. On this version, the soul is a bundle of powers (plus spiritual matter), and so is identical to the entire collection of its powers (plus spiritual matter). To defend this view, Olivi first considers and rejects another version of the identity theory, on which the soul is a single power capable of eliciting all of the different vital acts associated with a living being. His main argument against this position is that diverse forms of production or of activity require powers that are themselves diverse by nature or essence. Olivi then attacks the distinction theory developed, for instance, by Aquinas, arguing that, among other things, this theory conflicts with our conception of ourselves as essentially free and rational agents. Next, Olivi criticizes Bonaventure’s distinction theory, arguing that it is impossible for the soul’s powers to be substances and yet dependent on the soul itself. Finally, Olivi puts forward his own preferred bundle theory of the soul and its powers.

In this text, of which we have translated a large excerpt, Henry of Ghent rejects the view defended by Albert and Aquinas according to which powers are accidents distinct from the essence of the soul. Instead, he maintains, the soul is its powers “through its essence”. To show this, Henry devises an argument directed against Aquinas’ claim that a power must be in the same category as its act. The upshot of the argument is that this claim must be rejected because, along with some premises widely accepted by medieval Aristotelians, it leads to a (vicious) infinite regress. Additionally, Henry develops his own theory of the powers of the soul. While he thinks that the soul is its powers through its essence, he contends that the soul’s powers do add something to the soul, namely, relations to their acts. For example, the intellect is the soul as related to the act of thinking, whereas sight is the soul as related to the act of seeing. On the basis of this relational account Henry discusses in this text the distinction between those powers of the soul that are tied to a bodily organ, such as sight, and those that are not, such as the intellect.

In this text, Duns Scotus asks: does the image of the Trinity in the rational soul consist in three really distinct powers? His answer is in the negative. The powers of the soul, he maintains, are really the same as the soul, but formally distinct from it as well as from one another. To develop this view, Scotus first refutes several alternative theories, including Aquinas’ distinction theory and Henry’s relational account of powers. In his refutation of Aquinas, Scotus provides a discussion of the Category Argument, arguing that it confuses two distinct senses of the term ‘potency’, ‘potency’ understood as power and ‘potency’ understood as a non-actual mode of being. Against Henry, Scotus argues that the view that the powers of the soul are the soul as related to different acts entails that these powers must always be actualized. To develop his own account of the soul and its powers, based on the formal distinction, Scotus draws on the notion of unitive containment and his account of the transcendentals. He argues that the soul is explanatorily prior to its powers, arguing that it exists at a “first instant of nature” while its powers exist at a “second instant of nature”.