In vindicating human freedom, Plotinus had to encounter a difficulty exceedingly characteristic of his age. This was the astrological superstition that everything depended on the stars, and that the future fate of every person might be predicted by observing their movements and configurations at the time of his birth. Philosophers found it much easier to demolish the pretensions of astrology by an abstract demonstration of their absurdity, than to get rid of the supposed facts which were currently quoted in their favour. That fortunes could be foretold on the strength of astronomical calculations with as much certainty as eclipses, seems to have been an accepted article of belief in the time of Plotinus, and one which he does not venture to dispute. He is therefore obliged to satisfy himself with maintaining that the stars do not cause, but merely foreshow the future, in the same manner as the flight of birds, to the prophetic virtue of which he also attaches implicit credence. All parts of Nature are connected by such an intimate sympathy, that each serves as a clue to the rest; and, on this principle, the stars may be regarded as the letters of a scripture in which the secrets of futurity are revealed.[443] How much originality there may be in the anti-materialistic arguments of Plotinus we cannot tell. He certainly marks a great advance on Plato and Aristotle, approximating, in this respect, much more closely than they do to the modern standpoint. The indivisibility and permanence of mind had, no doubt, been strongly insisted on by those teachers, in contrast with the extended and fluctuating nature of body. But they did not, like him, deduce these characteristics from a direct analysis of consciousness as such. Plato inferred the simplicity and self-identity of mind from the simplicity and self-identity of the ideas which it contemplates. Aristotle went a step further, or perhaps only expressed the same meaning more clearly, when he associated immateriality with the identity of subject and object in thought.[444] Moreover, both Plato and Aristotle seem to have rested the whole spiritualistic case on objective rather than on subjective considerations; although, as we have seen, the subjective interest was what dominated all the while in their thoughts. Starting with the analogy of a living body, Plato argues, both in the _Phaedrus_ and in the _Laws_, that soul must everywhere be the first cause of motion, and therefore must exist prior to body.[445] The elaborate scientific analysis of Aristotle’s _Physics_ leads up to a similar conclusion; and the ontological analysis of the _Metaphysics_ starts with the distinction between Form and Matter in bodies, to end with the question of their relative priority, and of the objective machinery by which they are united. Plotinus, too, sometimes refers to mind as the source of physical order; but this is rather in deference to his authorities than because