The knowledge of anything, since all things have causes, is not acquired or complete unless it is known by its causes. Therefore in medicine we ought to know the causes of sickness and health. And because health and sickness and their causes are sometimes manifest, and sometimes hidden and not to be comprehended except by the study of symptoms, we must also study the symptoms of health and disease. Now it is established in the sciences that no knowledge is acquired save through the study of its causes and beginnings, if it has had causes and beginnings; nor completed except by knowledge of its accidents and accompanying essentials. Of these causes there are four kinds: material, efficient, formal, and final.

Those who deny the first principle should be flogged or burned until they admit that it is not the same thing to be burned and not burned, or whipped and not w…

An ignorant doctor is the aide-de-camp of death.

It is evident that everything which does not exist at first and then exists, is determined by something other than itself.

At the same time this is an extremely important practical application of the power of human knowledge, which may also be of immediate use to man, who, due to t…

I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in nu…

I am on the edge of mysteries and the veil is getting thinner and thinner.