I've been working through Peter Thomae's unpublished
De formis, a treatise that like all his treatises defies assignment to a classical medieval genre. Is it natural philosophy? Or metaphysics? It is a thorough investigation utilizing all the knowledge about form from the middle ages. My interest in it is partially because I am comitted to publish it as part of the general Petri Thomae opera series, but also because of its relation, or non-relation to Scotus. As is well known, Scotus left us no commentary or set of questions on the
Physics. His followers then had to fill in the gap and develop a "scotist" natural philosophy. Peter seems to use the available works on Scouts, which I suppose is unsurprsing. He relies on the
De primo principio for the relation of matter and form, and sometimes cites Scotus'
Quaestiones super Metaphysicam and Ordinatio as well. Peter Thomae also uses more Aquinas in this work than he does in others. While elsewhere Peter has a decidedly non-adversarial approach to Aquinas (quoting Aquinas on the primacy of the concept of being without taking him to task over the object of the intellect), here in the
De formis Peter is more critical.
Sadly, the De formis survives in only 1 manuscript, that is heavily damaged, and the scribe is the same one from the De esse intelligibili, who is an extremely poor copyist. Thus this may well be the most challenging entry in the Petri Thomae opera.
Here is Peter's description of form from the beginning of the work, after he has surveyed the definitions of Aristotle, Averroes, Augustine, and Avicenna. Following the definition he breaks it down word by word in true medieval style and offers commentary on it.
Quaestiones de formis, q. 1 a. 2:
forma est pars essentialis compositi, alterius eiusdem partis actuativa simpliciter, ab eo tamen dependens in fieri et in esse, vel in esse tantum vel compositi, principaliter essentiativa vel specificativa.
Form is an essential part of the composite, absolutely actuating the other part of the composite, yet depending upon it both in being and in becoming, or in the being alone of the composite, essentiating and specifying [the composite].