The Ether

Von Stephen Howard (Leuven)

It goes without saying that Kant’s most glaring errors are his views on race and gender, which will be discussed by other contributors. So, bearing in mind that my topic is of secondary importance, let me mention a different way in which Kant seems not to be our contemporary. In his early writings as well as in the final drafts he wrote at the end of his life, Kant showed himself to be an enthusiastic believer in the ether: an all-penetrating matter that is the bearer of forces and, in particular, light and heat.

The early Kant scholar Erich Adickes accused Kant of backing the wrong horse, so to speak, by affirming the substantiality theory of heat – according to which the ether is the substance (Stoff) of heat – rather than the vibration theory that later became standard. Kant was not the only natural philosopher who tried to explain heat on the basis of the ether: so did Boerhaave, Euler and Lavoisier. Thinkers such as Descartes and (in his unguarded moments) Newton speculated that the ether could explain gravitational attraction. The ether concept was only decisively disqualified in the late nineteenth and early twentieth century: experimentally by Michelson and Morley, and theoretically by Einstein.

When criticizing Kant, it is tempting to employ his own conception of critique, which entails not simply rejecting a view but rather identifying its sphere of validity and the limits of this validity (this conception of critique is not outdated, I would say). In this spirit we might say that the ether has value as part of our ‘manifest’ rather than ‘scientific’ image of the world, to borrow Sellars’ distinction. We tend to find it difficult to conceive of forces without something that carries them. And who knows: in future physical theories that try to explain, or reject, dark matter and dark energy, the ether might make a comeback.