Certainly it seems that nature desires to exterminate the human race, as a thing useless to the world, and the destroyer of all created things. - Leonardo da Vinci

Every action needs to be prompted by a motive. To know and to will are two operations of the human mind. Discerning, judging, deliberating are acts of the human mind.

Men do wrong to lament the flight of time, complaining that it passes too quickly and failing to perceive that its period is sufficiently long; but a good memory, with which nature has endowed us, causes everything that is long past to appear to us to be present.

Amid the vastness of the things among which we live, the existence of nothingness holds the first place; its function extends over all things that have no existence, and its essence, as regards time, lies precisely between the past and the future, and has nothing in the present. This nothingness has the part equal to the whole, and the whole to the part, the divisible to the indivisible; and the product of the sum is the same whether we divide or multiply, and in addition as in subtraction; as is proved by arithmeticians by their tenth figure which represents zero; and its power has not extension among the things of Nature.