PART 20
XX. Certain physicians and philosophers assert that
nobody can know medicine who is ignorant what a
man is ; he who would treat patients properly must,
they say, learn this. But the question they raise is one
for philosophy ; it is the province of those who, like
Empedocles, have written on natural science,
1 what
man is from the beginning, how he came into being
at the first, and from what elements he was originally
constructed. But my view is, first, that all that
philosophers or physicians have said or written on
natural science no more pertains to medicine than to
painting.
2 I also hold that clear knowledge about
natural science can be acquired from medicine and
from no other source, and that one can attain this
knowledge when medicine itself has been properly
comprehended, but till then it is quite impossible--I
mean to possess this information, what man is,
by what causes he is made, and similar points
accurately. Since this at least I think a physician
must know, and be at great pains to know, about
natural science, if he is going to perform aught of his
duty, what man is in relation to foods and drinks,
[p. 55]
and to habits generally, and what will be the effects
of each on each individual. It is not sufficient to
learn simply that cheese is a bad food, as it gives a
pain to one who eats a surfeit of it ; we must know
what the pain is, the reasons for it, and which constituent
of man is harmfully affected. For there are
many other bad foods and bad drinks, which affect a
man in different ways. I would therefore have the
point put thus :--"Undiluted wine, drunk in large
quantity, produces a certain effect upon a man." All
who know this would realise that this is a power of
wine, and that wine itself is to blame,
3 and we know
through what parts of a man it chiefly exerts this
power. Such nicety of truth I wish to be manifest
in all other instances. To take my former example,
cheese does not harm all men alike ; some can eat
their fill of it without the slightest hurt, nay, those
it agrees with are wonderfully strengthened thereby.
Others come off badly. So the constitutions of these
men differ, and the difference lies in the constituent of
the body which is hostile to cheese, and is roused and
stirred to action under its influence. Those in whom
a humour of such a kind is present in greater quantity,
and with greater control over the body, naturally suffer
more severely. But if cheese were bad for the human
constitution without exception, it would have hurt
all. He who knows the above truths will not fall
into the following errors.
