These general notions being admitted, let us inquire into the principles of accidental compounds. An accidental compound is either a compound of substance and accident or a compound of real essence with something superadded. In the first case, “accidental” means the opposite of “substantial”; in the second case, “accidental” means the opposite of “essential.” Thus _a falling body_ is an accidental compound of substance and its momentum, the momentum being a real accident; whereas _a man clothed_ is an accidental compound of individual human nature and dress; the dress being considered as something accidental as compared with the essence of man, though it is a real substance. And in the same manner a mass of gold is an accidental compound of golden molecules, because each molecule fully possesses the essence of gold independently of any other molecule; whence it follows that the addition of other molecules is accidental as compared with the essence of gold, and only increases the quantity without altering the specific nature of gold. Of course, these other molecules are substances, and it is only their concurrence into one mass that is accidental. It is plain that the constituent principles of an accidental compound are three—viz., _the accidental act_ which entails a modification of the subject; _the subject_ which receives the modifying act; and _the accidental mode_ of being, or the modification, which results from the reception of the act in the subject. The subject is always a complete physical being, and, therefore, has its own essential act, term, and complement, independently of all things accidental. It becomes the subject of an accidental act by actually receiving it. The accidental act which is received in the subject must proceed immediately from the action of some natural or supernatural agent. This is evident; for real receptivity is real passivity, and therefore reception is passion. Now, no passion can be admitted without a corresponding action. Hence all accidental act that is properly and truly _received_ in a subject is the immediate product of action, and its production exactly coincides and coextends with its reception.