III

Aristotle holds that chance is an accidental cause and not one of his four causes ¹³ According to Aristotle, a chance event is accidental to a substantial cause. ¹⁴ In Phys. II, viii, Aristotle considered and rejected chance as a cause of nature.

Why then should it not be the same with the parts in nature, e.g. that our teeth should come up of necessity-the front teeth sharp, fitted for tearing, the molars broad and useful for grinding down the food-since they did not arise for this end, but it was merely a coincident result; and so with all other parts in which we suppose that there is purpose? … Such are the arguments (and others of the kind) which may cause difficulty on this point. Yet it is impossible that this should be the true view. For teeth and all other natural things either invariably or normally come about in a given way; but of not one of the results of chance or spontaneity is this true. (198b24-28, 32-25)

Without being considered one of the four causes, Aristotelian chance is an accidental cause pertaining to a substantial cause, i.e. any one of the four causes. Any of Aristotle’s four causes can be a substantial cause, i.e. a per se cause, which chance can pertain to. Existing in Aristotle’s teleological context, all of the four causes are goal oriented. ¹⁵ A chance event pertains to a substantial cause becomes meaningful as a result of nature or intellect. For example, when Newton saw the apple falling from the tree, Newton’s intellect was at work for him to recognize the significance which allowed him to connect the chance event of seeing the falling apple with the forces of nature. His recognition of the significance of the falling apple is the efficient cause of his discovery of the laws of gravity and the fall of the apple that he saw was pertaining to this efficient cause. Similarly, Alexander Fleming’s intellect recognized that something significant was involved when he observed the aftermath of the carelessly handled lab sample. The recognition was the efficient cause while the carelessly handled lab sample itself, the chance event, was pertaining to this efficient cause.

Another characteristic of Aristotelian chance is that it stands in contrast to necessity and it is for occurrences that are not “always or for the most part.” He says:

First, then, since we see somethings always coming to be in the same way, and some for the most part, it is evident that neither luck nor what is due to luck is said to be the cause of either of these – either of what is of necessity and always, or of what is for the most part. But since there are also things which happen in addition to these, and all say that these happen from luck, it is evident that luck and chance are something. For we know that such things are from luck and that the things due to luck and of this kind.

Aristotelian chance is of unusual occurrence. When Aristotle rejects the view that nature is a result of chance (Phys, II. Viii), his reasoning is that nature, e.g. teeth are sharp, occurs always or for the most part and therefore is not chance.