Science and Reason

There is no object so large but that at a great distance from the eye it does not appear smaller than a smaller object near.

You should prefer a good scientist without literary abilities than a literate one without scientific skills.

Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.

The merit of painting lies in the exactness of reproduction. Painting is a science and all sciences are based on mathematics. No human inquiry can be a science unless it pursues its path through m a t h e m a t i c a l e x p o s i t i o n a n d demonstration.

To me it seems that those sciences are vain and full of error which are not born of experience, mother of all certainty, first-hand experience which in its origins, or means, or end has passed through one of the five senses.

Test knowledge through experience, be prepared to make mistakes, and be persistent about it.

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.

Common Sense is that which judges the things given to it by other senses.

A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements.

Motion is created by the destruction of balance.

I roamed the countryside searching for answers to things I did not understand. Why shells existed on the tops of mountains. How the various circles of water form around the spot which has been struck by a stone, and why a bird sustains itself in the air.

The Book of the science of Mechanics must precede the Book of useful inventions.

Drawing is based upon perspective, which is nothing else than a thorough knowledge of the function of the eye.

Science is the observation of things possible, whether present or past; prescience is the knowledge of things 50 which may come to pass, though but slowly.

There is no higher or lower knowledge, but one only, flowing out of experimentation.

Science is the captain, and practice the soldiers.

It’s not enough that you believe what you see. You must also understand what you see.

Perspective is to painting what the bridle is to the horse, the rudder to a ship.

Although nature commences with reason and ends in experience it is necessary for us to do the opposite, that is to commence with experience and from this to proceed to investigate the reason.

All objects transmit their image to the eye in pyramids and the nearer to the eye these pyramids are intersected the smaller will the image appear of the objects which cause them.

Avoid the precepts of those thinkers whose reasoning is not confirmed by experience.

The faculty of imagination is both the rudder and the bridle of the senses.

It is useful to constantly observe, note, and consider.

Strive to preserve your health; and in this you will better succeed in proportion as you keep clear of the physicians, for their drugs are a kind of alchemy concerning which there are no fewer books than there are medicines.