Even granting these things whence came the knowledge of...

Even granting these things whence came the knowledge of advantages and disadvantages of medicine? Why this affected a cure and this an injury-their nature their sweet and bitter tastes the softness of one and the hardness of the other? If you answer, by pondering, I say it is impossible; because these things are beyond the scope of the senses and cannot be comprehended by thought.

You cannot say either it was by personal test; for had he made experiments upon himself he must have died from some poisonous…