Thomas Aquinas

“ To the moralist, in so far as with respect to circumstances we find or lose the mean of virtue in human acts and passions. To the politician and to the orator, in so far as circumstances make acts to be worthy of praise or blame, of excuse or indictment. In different ways, however: because where the orator persuades, the politician judges. To the theologian this consideration belongs, in all the aforesaid ways: since to him all the other arts are subservient: for he has to consider virtuous and vicious acts, just as the moralist does ”

“ Thus, in regard to the object, it is not a circumstance of theft that the object is another's property, for this belongs to the substance of the act; but that it be great or small. And the same applies to the other circumstances which are considered in reference to the other causes. For the end that specifies the act is not a circumstance, but some additional end. Thus, that a valiant man act "valiantly for the sake of" the good of the virtue or fortitude, is not a circumstance; but if he act valiantly for the sake of the delivery of the state, or of Christendom, or some such purpose. ”

“ But oratorical arguments are derived principally from things pertaining to the essence of a thing, such as the definition, the genus, the species, and the like, from which also Tully declares that an orator should draw his arguments. Therefore a circumstance is not an accident of a human act.
Objection 2: Further, "to be in" is proper to an accident. But that which surrounds [circumstat] is rather out than in. Therefore the circumstances are not accidents of human acts.
Objection 3: Further, an accident has no accident. But human acts themselves are accidents. ”