Unphilosophic

Light is a term merely relative to us; but light itself has no absolute existence any more than sound: then how unphilosophic are the terms latent light, and light in darkness, which we sometimes hear—as if that which is merely an effect could be regarded as a cause, or as a physical force, at the same time that we know it is not possible to demonstrate the existence of any other physical force in nature than electricity.