But to me all sciences seem vain and full of error that are not born of experience, mother of all certainty, and do not terminate in an actual experience.

I say that the power of vision extends through the visual rays to the surface of non-transparent bodies, while the power possessed by these bodies extends to the power of vision.

Who sows virtue ought to reap honour.

If you find from your own experience that something is a fact and it contradicts what some authority has written down, then you must abandon the authority and base your reasoning on your own findings.

A bird maintains itself in the air by imperceptible balancing, when near to the mountains or lofty ocean crags; it does this by means of the curves of the winds which as they strike against these projections, being forced to preserve their first impetus bend their straight course towards the sky with divers revolutions, at the beginning of which the birds come to a stop with their wings open, receiving underneath themselves the continual buffetings of the reflex courses of the winds.

Wisdom is the daughter of experience

A wave is never found alone, but is mingled with as many other waves as there are uneven places in the object where the said wave is produced.