"To be conscious of free will," says Stuart Mill, "must mean to be conscious, before I have decided, that I am able to decide either way.[8] This is really the way in which the defenders of free will understand it; and they assert that when we perform an action freely, some other action would have been "equally possible." On this point they appeal to the testimony of consciousness, which shows us, beyond the act itself, the power of deciding in favour of the opposite course. Inversely, determinism claims that, given certain antecedents, only one resultant action was possible. "When we think of ourselves hypothetically," Stuart Mill goes on, "as having acted otherwise than we did, we always suppose a difference in the antecedents. We picture ourselves as having known something that we did not know, or not known something that we did know."[9] And, faithful to his principle, the English philosopher assigns consciousness the rôle of informing us about what is, not about what might be. We shall not insist for the moment on this last point: we reserve the question in what sense the ego perceives itself as a determining cause. But beside this psychological question there is another, belonging rather to metaphysics, which the determinists and their opponents solve _a priori_ along opposite lines. The argument of the former implies that there is only one possible act corresponding to given antecedents: the believers in free will assume, on the other hand, that the same series could issue in several different acts, equally possible. It is on this question of the equal possibility of two contrary actions or volitions that we shall first dwell: perhaps we shall thus gather some indication as to the nature of the operation by which the will makes its choice. [Sidenote: Geometrical (and thereby deceptive) representation of the process of coming to a decision.] I hesitate between two possible actions X and Y, and I go in turn from one to the other. This means that I pass through a series of states, and that these states can be divided into two groups according as I incline more towards X or in the contrary direction. Indeed, these opposite inclinations alone have a real existence, and X and Y are two symbols by which I represent at their arrival-or termination-points, so to speak, two different tendencies of my personality at successive moments of duration. Let us then rather denote the tendencies themselves by X and Y; will this new notation give a more faithful image of the concrete reality? It must be noticed, as we said above, that the self grows, expands, and changes as it passes through the two contrary states: if not, how would it ever come to a decision? Hence there are not exactly two contrary states, but a large number of successive and different states within which I distinguish, by an effort of imagination, two opposite directions. [Illustration]