Book I

Many of the finest physicians have written about the properties of K. VI foods, taking the subject very seriously since it is about the most valuable 453 of any in medicine. For while we do not invariably make use of other resources, life without food is impossible, be we well or ill. So it is understandable that most of the best physicians have been concerned to 454 examine its properties in some detail, some alleging that they had come to know them from experience alone, others wanting to employ theoretical argument as well, while still others considered this latter to be the most important.

Now, if in their writings about food they were in agreement about everything (as is the case with people who write about geometry and arithmetic), there would now be no need for me to take the trouble to write again about the same things in addition to so many such men. But since by holding differing views they have raised suspicions about one another (for they cannot all be speaking the truth!) we must become impartial judges and put what they have said to the test. For without demonstration it is wrong to put one's confidence in one more than the others.