Hi, I'm Peter Adamson, and you're listening to the History of Philosophy podcast, brought to you with the support of the Philosophy Department at Keynes College London and the LMU in Munich, online at historyoflowsvy.net.

Today's episode. Life is not enough. Medicine in Renaissance France.

There is a scene in the imaginary invalid by the 17th century playwright, Maria, that is famous among philosophers.

It depicts an examination for entry to study medicine at Paris. The candidate is asked to explain why opium causes sleep, and answers that it is because opium has a dormative power, a virtus dormitiva,

that is the power to put people to sleep. This vacuous triviality is of course exactly what his foolish scholastic examiners are looking for, and the candidate gets full marks for it.

Which is all good fun, but let's face it, it's not as if Maria had a better answer to give.

In fact, you could make a good case that ascribing a dormative power to opium is not vacuous after all.

Ascribing a power to the opium is a meaningful scientific proposal, which differs from, say, asserting that the more rudimentary material ingredients of opium cause sleep, perhaps by cooling down the body.

Instead, the dormative power ascribes to the nature of opium, a disposition for affecting the world, one that cannot be reduced to other natures, and one that cannot be explained in terms of the perceptible properties of opium.

I'm not saying that the dormative power is a good explanation mind you, but I am saying that it is meaningful and that it may have been about as good an explanation as anyone at the time could have offered.

As it happens, people back in the 16th century, when mockery of scholastics was a more novel enterprise, devoted serious thought to the effects of opium.

A study of doctors at the University of Leiden has shown how physicians there wrestled precisely with the problem that the sensible properties of opium do not seem to match its effects.

Apparently, it tastes hot, kids don't try this at home, yet it has this soperefic effect which we'd expect to relate to cooling since the body is cooler during sleep.

Some of the Leiden doctors inferred that the powers of drugs cannot be investigated using sensation, or at least not always.

One of them, Gilbert Jacheus, said that we need to draw a distinction between the evident and hidden or occult powers of natural substances.

With this, he echoed a real life doctor of Paris, Jean-Fannell, who authored a long treatise whose very title was, on the hidden causes of things.

It was published in 1548, with a dedication to the king Henry II, later on during his reign, Fannell would become royal physician.

In the preface, he speaks of his desire to uncover what is divine within the art of medicine, with what follows being the fruits of his labor.

It takes the form of a dialogue between three scholars, the two main protagonists being Brutus and Udoxus.

The names are none too subtly chosen, since Brutus is rather brutish in his manners, a fact that may be linked to his favoured theories.

He believes that the nature's powers and dispositions of substances can indeed be explained in terms of their brute material ingredients.

The forms of things emerge from the bottom up, out of mixtures of these ingredients.

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