Diocles of Carystus on the method of dietetics 99
the ‘highly useful distinction’ (
!) between ‘foodstuffs’ ( )
and ‘drugs’ ( ) – that is to say, for not having pointed out under
what circumstances a particular substance acts like a foodstuff (which only
preserves the state of the body) or as a drug (which changes the state of
the body) – just as he failed to deal, Galen adds maliciously, with the other
distinctions discussed by him in the previous paragraphs.
In fact, in the context of another treatise, namelyOn Medical Experience
(De experientia medica,De exp. med.),^57 Galen expresses himself in a much
more positive way on Diocles’ position, although his characterisation of it
seems to be based on the same passage from Diocles’Matters of Health to
Pleistarchus:
As for me, I am surprised at the sophists of our age, who are unwilling to listen to
the word of Hippocrates when he says: ‘In the case of food and drink experience
is necessary’, and are not content to accept for themselves and their followers
an opinion concerning which the generality of men are completely unanimous,
to say nothing of the ́elite. For if everything which is ascertained is ascertained
only by reasoning, and nothing is ascertained by experience, how is it possible
that the generality, who do not use reason, can know anything of what is known?
And how was it that this was unanimously asserted among the elder doctors,
not only by Hippocrates, but also by all those who came after him, Diogenes,
Diocles, Praxagoras, Philotimus, and Erasistratus? For all of these acknowledge that
what they know concerning medical practice they know by means of reasoning in
conjunction with experience. In particular, Diogenes and Diocles argue at length
that it is not possible in the case of food and drink to ascertain their ultimate effects
but by way of experience.In this testimony, the view of Diocles and the other ancient authorities
is obviously referred to in order to support Galen’s argument against an
exclusivelytheoreticalapproach to medicine. And although we should not
assign much independent value to this testimony – which, apart from its
vagueness, is a typical example of Galen’s bluffing with the aid of one of
his lists of Dogmatic physicians – it is compatible both with the picture
of Diocles’ general medical outlook that emerges from the collection of
fragments as a whole and with his approach to dietetics as reflected in our
fragment 176. Diogenes and Diocles are mentioned by Galen in particular
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).(^57) Fr. 16 (Galen,De exp. med. 13. 4 – 5 ,p. 109 Walzer, whose translation I have adopted, except for
the translation oflogos, which Walzer leaves untranslated but which I have rendered by ‘reason’)
[see n. 58 ]; this fragment is also (but obviously for different reasons) lacking in Wellmann.