The Common Principles of Natural Philosophy

...a singular species, and the universal [produces] a universal one. The species of a universal thing and a singular thing are similar to one another, just as the universal and singular themselves are. Hence, "man" the universal category of humanity exists within "this man" the specific individual, and it cannot exist without the species of the singular thing wherever it may be—whether in the mediumoriginal: "medio"; the substance, such as air or water, through which a force or light travels., in the sense, or in the intellect.

5 Furthermore, a natural agentoriginal: "agens"; the entity that performs an action or exerts power. does not emit anything [physical] from itself, because an accidentoriginal: "accidens"; a quality or property (like color, heat, or size) that exists in a substance but is not part of its essential nature. cannot be separated from it. For accidents are of an unyielding nature original: "indignantis nature"; a metaphorical way of saying accidents are "stubborn" and cannot exist independently of a subject.; they can be destroyed within their subjectsoriginal: "subjectis"; the physical things in which qualities like color or heat reside., but they are by no means able to be changed by them, nor can they

10 pass into other subjects. For example, the color in a wall cannot be separated from it to be placed in another thing; everyone concedes this.

Moreover, nothing of the substanceoriginal: "substancie"; the essential "stuff" or underlying reality of a thing, as opposed to its outward qualities. can be separated from the agent through its action, because then there would be a loss of substance through its action and a corruption of the thing, which is not true. For the celestial spiritual beings are

15 most active, yet they do not undergo loss of substance or corruption. Nor is there a counter-example in a fragrant thing original: "odorabili", from which odorous smoke exits (as we see in burning incense). This is because the smoke is not emitted insofar as the fragrant thing is an agent, but insofar as it is a patientoriginal: "paciens"; the entity that receives an action or is acted upon by an external force.. For it suffers from external or internal heat, as in musk and other aromatics;

20 because heat dissolves the subtle vapors which belong to the substance of the fragrant thing. These vapors are physical bodies dispersed through the air, dividing the parts of the air because the air is thinner than they are and yields to them. Therefore, the fragrant thing, insofar as it is a patient, emits something of its substance;

5 b 2. | but not insofar as it is an | agent. For as an agent, it produces something outside
F. 86 a 2. 25 of itself in the body presented to it, which is called "species" and "virtue" original: "virtus"; here meaning "power" or "potency.", and it is neither substance nor accident.

Nor is that opinion true which claims that celestial form can multiply matter continuously without loss, and that through this multiplication the species of the sun and stars is produced in these

30 lower regions. This position is entirely false, as can be evident to anyone in my Metaphysics original: "Methaphisica". For now, it suffices to say briefly that the generation of species is similar in all things, since it is a univocal actionoriginal: "accio univoca"; an action where the cause produces an effect of the same nature as itself (like fire producing heat)., through which the first univocal effect is produced...