All our knowledge has its origin in our perceptions. - Leonardo da Vinci

Every quantity is intellectually conceivable as infinitely divisible.

You will perhaps say that the sinews and muscles of a bird are incomparably more powerful than those of a man... But the reply to this is that such great strength gives it a reserve of power beyond what it ordinarily uses...

Though I may not, like them, be able to quote other authors, I shall rely on that which is much greater and more worthy – on experience, the mistress of their Masters.