BOOK I. XI. 28-35
for the motive anywhere outside of ourselves, but that in all cases it is one and the same thing that is the cause of our doing a thing or of our not doing it, of our saying things, or of our not saying them, of our being elated, or of our being cast down, of our avoiding things, or of our pursuing them—the very thing, indeed, which has even now become a cause of my action and of yours; yours in coming to me and sitting here now listening, mine in saying these things. And what is that? 30Is it, indeed, anything else than that we wanted to do this?—Nothing.—And supposing that we had wanted to do something else, what else would we be doing than that which we wanted to do? Surely, then, in the case of Achilles also, it was this that was the cause of his grief—not the death of Patroclus (for other men do not act this way when their comrades die), but that he wanted to grieve. And in your case the other day, the cause of your running away was just that you wanted to do so; and another time, if you stay with her, it will be because you wanted to stay. And now you are going back to Rome, because you want to do so, and if you change your mind and want something else, you will not go. And, in brief, it is neither death, nor exile, nor toil, nor any such thing that is the cause of our doing, or of our not doing, anything, but only our opinions and the decisions of our will.
Do I convince you of this, or not?—You convince me, said he.—Of such sort, then, as are the causes in each case, such likewise are the effects. 35Very well, then, whenever we do anything wrongly, from this day forth we shall ascribe to this action no other cause than the decision of our will which led us to
