art; and therefore we say it was an accident, and while there is a sense in which he makes it, in the full sense he does not make it. — For some accidental results sometimes tend to be produced by alien potencies [1] but to others there corresponds no determinate art nor potency; for of things which are or come to be by accident, the cause also is accidental. Therefore, since not all things are or come to be of necessity and always, but the majority of things are for the most part, the accidental must exist; for instance a white man is not always nor for the most part musical, but since this sometimes happens, it must be accidental. If not, everything will be of necessity. The matter, therefore, which is capable of being otherwise than as it usually is, is the cause of the accidental. And we must take as our starting-point the question whether everything is either always or for the most part. Surely this is impossible. There is, then, besides these something which is fortuitous and accidental. But while the usual exists, can nothing be said to be always, or are there eternal things? This must be considered later,[2] but that there is no science of the accidental is obvious; for all science is either of that which is always or of that which is for the most part. For how else is one to learn or to teach another? The thing must be determined as occurring either always or for the most part, e.g. that honey-water is useful for a patient in a fever is true for the most part. But one will not be able to state when that which is contrary to the usual law happens, e.g. 'on the day of new moon';[3] for if one can say this, 'on the day of new moon' is itself the statement of a universal or a usual law; but the accidental is contrary to such laws. We have stated, then, what the accidental is and from what cause it arises, and that there is no science which deals with it.
Chapter 3
That there are principles and causes which are generable and destructible without ever being in course of being generated or destroyed, is obvious. For otherwise all things will
