Those depths, Idealists like Immanuel Kant believe, lie beyond sensory perception, but are every bit as real as the unseen lake bed. More real, in fact, than the fleeting sensory phenomena we typically experience. Philosophers have given this unseen reality various names. Kant called it the noumenon. Plato called it the world of Ideal Forms. For Indian philosophers, it is Brahman. Different names but the same idea: a plane of existence that remains unknown to us as we rush to work, binge-watch Netflix, and, in general, go about our business in the world of shadows.
