The five days debate at Cicero's house in Tusculum between master and sophister.

SECT. XXIII. Arguments for the Immortality of the Soul, from its inward Motion.

WHat always moveth, is eternal; but what im∣parts motion to another, and what is acted by another, when it comes to an end of motion, must also come to an end of life. That only therefore which moves it self, because it is never deserted of it self, neither doth it ever cease moving; nay, this is the Spring, this the Principle of Motion, to other things which are mov'd. Now a Principle hath no precedent source of being, for all things arise from their Principle, but it can spring from no other thing; for so it would cease to be a Prin∣ciple, if it were begotten of any thing else; but if it be never generated, neither will it ever corrupt; for a Principle abolish'd, can neither arise again from another, nor can it produce any other thing from it self; for all things must necessarily arise from their Principle; so cometh it about, that the Principle of Motion, must be at that which moveth it self; now that can neither be born, nor dye; or else all Heaven would tumble down, and the whole frame of Nature stop its course; nor have any Mover, by whose first impression it should be set on Motion. It being therefore plain, that what moves it self, is eternal, who can deny the Nature of Souls to be such; for whatsoever is stir'd by a foreign Impression, is inanimate; but every Animal is quickened by an in∣ward Motion, and of its own; for that is the proper

Nature and Power of the Soul; which if it be the only of all Substances, that alwayes moves it self; neither was it in truth ever born, and is eternal.

Let all the petty Philosophers (for so should they be call'd, in my opinion, who differ from Plato and Socrates, and that Family) let them come in to assist one another; they will not only never ex∣press any thing so neatly, but also never be able to discern where the stress of the Argument lyes. (e) The Soul therefore is sensible that it moves, and is withall sensible that it moves by its own, and no foreign Impulse; and that it can never be, that it should fail it self, from whence its Eternity is concluded, unless you have any reply to offer.

S. I indeed, am well contented, to admit in∣to my thought, no matter of questioning it, I have such a favour for that Opinion.

(e) The Soul therefore is sensible that it moves.] The former Argument of Self-motion, being common to all living Creatures; might seem to conclude for the like Privilege to the Souls of brute Beasts which go downward, and re∣turn into the Power of that Matter, from whence they were educed: But Cicero restrains it to a reflex Act, of the understanding which properly flows from the rational Soul.