What is the biomedical model #3

Over the last few weeks, we’ve been running a series of blog posts on the biomedical model. Biomedicine is, without doubt, one of the most powerful discourse affecting the way physiotherapists think and practice, but it is also rarely explained or explored. So over the next few blog posts I’ll be unpacking its essential features.

The first two posts in the series focused on specific aetiology and germ theory. In this post, we’re going to tackle Cartesian Dualism.

Cartesian Dualism gets it’s name from the work of the French skeptical philosopher Rene Descartes (1596-1650) who, perhaps more than anyone, captured the zeitgeist of the Renaissance by defining a distinction between the mind (the seat of reason, God-like and pure) and the body (profane, messy and prone to breaking down). This distinction between the body and the mind persists today and gives us the binary part of Cartesian Dualism.

In crude terms, Descartes made it possible for Enlightenment natural philosophers to think of the body as distinctive from the mind, and to thereby separate it from some of the restrictions imposed by the church at the time. Descartes essentially paved the way for a profession and science of medicine at a time when the workings of the body had become something of a fascination for early scientists.

But Descartes did more than this. In a famous argument that became a cornerstone of philosophical thinking, Descartes argued that at any time a pink elephant (or whatever variation of fantastic object we might want to consider) might appear under the table in front of us. He argued that because our dreams were so lifelike, and were such a vivid projection of reality, we could never really know or prove that we were not, right now, dreaming. And if we were in a dream state, anything could be possible; even a pink elephant appearing from under the table. Crucially, if we could not prove that we were not dreaming, we could not actually prove the real existence of anything. Everything could, in theory, be a projection of a dream state.

Descartes argued that the only thing we could say for sure is that we are consciously contemplating our own existence. We know we are thinking about being in a dream, and so we can, at least, say that we exist, because we are the ones doing the thinking. Hence Descartes famous phrase cogito ergo sum; I think, therefore I exist.

Our inability to prove the existence of real things (this table, this alveolus, this movement), led those that followed Descartes to contemplate how we could at least get ‘close’ to showing that some things were real. Science relies on the fact that things are real and that natural laws affect the behaviour of things; it looks for predictable cause and effect relationships. So science needed a strong foundation in methods that might, at least, approximate reality.

Hence, for centuries, scientists have emphasized objective methods of testing that do their best to remove the bias of the observer from the study. We use information from all of our sense and multiple sources in the hope of triangulating our data and verifying, beyond reasonable doubt, that the effect of this on that is a real effect and not an artifact of our perception. And we use statistical concepts like probability to specify those chance occurrences that pollute the purity of our data.

It might be said that without Rene Descartes, there could be no medical science. His works fundamentally shaped the way medicine and its related disciplines thought and practiced, and his ideas still cast an impressively long shadow over healthcare even today.