Perfect and Essential Goodness

Axiom of Pseudo-Dionysius: “That act is good whose causes are complete; that act is evil in which a single cause is lacking.”

(a) This axiom can be understood as referring to perfect good, and the meaning then is that an act is not perfectly good in the moral sense unless all its elements—its object, purpose and circumstances—are good; just as an oration is not called perfect, unless all its elements—the speaker, the matter, the style and the delivery—are what they should be. Hence, a single defect is enough to make an act fall short of perfection.

(b) The axiom can be understood of essential goodness, and the meaning then is that an act is not essentially good unless all the causes that contribute to essential goodness—the object of the act and any circumstances that may through the intention of the agent take on the character of object—are good; just as a man is not said to be healthy, unless his heart, lungs, and all the other chief parts of the body are sound. Hence, an act is substantially bad, if either its own end (the object of the act) or the special purpose had in mind by the agent (the end of the agent) is bad, as explained above in 79-81.

The axiom of Dionysius does not mean: (a) that an act cannot be essentially or substantially good and at the same time accidentally bad (see 78), for, if even one circumstance not properly attended to could change an act from good into bad, how few good acts would be done even by the most saintly persons! Example: Caius who sacrifices himself for the service of God and his neighbor, now and then feels some slight vanity over his work. His acts remain substantially good. (b) The axiom does not mean that an act cannot be substantially bad and yet have good circumstances that diminish its badness (see 81).