things: namely (1) that very often there really is some distinction between the two things, corresponding to the language which we use; (2) that this distinction, which really does subsist between the things, is the one which we mean to express by saying that the one was possible and the other impossible; and (3) that this way of expressing it is a perfectly proper and legitimate way. But if so, it absolutely follows that one of the commonest and most legitimate usages of the phrases “could” and “could not” is to express a difference, which often really does hold between two things neither of which did actually happen. Only a few instances need be given. I could have walked a mile in twenty minutes this morning, but I certainly could not have run two miles in five minutes. I did not, in fact, do either of these two things; but it is pure nonsense to say that the mere fact that I did not, does away with the distinction between them, which I express by saying that the one was within my powers, whereas the other was not. Although I did neither, yet the one was certainly possible to me in a sense in which the other was totally
