If everything when it occupies an equal space is at rest, and if that which is in locomotion is always occupying such a space at any moment, the flying arrow is therefore motionless.
For it is not true, as some treatise-mongers lay down in their systems, of the probity of the speaker, that it contributes nothing to persuasion; but moral character nearly, I may say, carries with it the most sovereign efficacy in making credible.
Everything necessarily is or is not, and will be or will not be; but one cannot divide and say that one or the other is necessary.I mean, for example: it is necessary for there to be or not to be a sea-battle tomorrow; but it is not necessary for a sea-battle to take place tomorrow, or for one not to take place--though it is necessary for one to take place or not to take place.
Everything that depends on the action of nature is by nature as good as it can be, and similarly everything that depends on art or any rational cause, and especially if it depends on the best of all causes.
Even when laws have been written down, they ought not always to remain unaltered. As in other sciences, so in politics, it is impossible that all things should be precisely set down in writing; for enactments must be universal, but actions are concerned with particulars. Hence we infer that sometimes and in certain cases laws may be changed.
The knowledge of the soul admittedly contributes greatly to the advance of truth in general, and, above all, to our understanding of Nature, for the soul is in some sense the principle of animal life.