Philosophers since Descartes have questioned whether our experience reflects a reality outside of our minds. In this instalment of our idealism series, in partnership with the Essentia Foundation, Paul Franks argues that the basic insight of Kant’s approach - perspectivism - harmonizes far better with our ordinary experience of the world, and with Einstein’s relativistic physics, than Berkeley’s immaterialist view.

For all I know on the basis of my current experience alone, I could be living in the matrix instead of inhabiting the mind-independent world. My experience could seem just as it seems right now, but it could be caused by something other than the mind-independent world in which I take myself to perceive and act. This familiar thought may be motivated by consideration of dreams, as it was for Descartes, or by more contemporary reflections on virtual reality. From this thought, many philosophers have inferred that what I perceive at any given moment is always and only mind-dependent, an inner world.  Kant calls this empirical or material idealism: the objects we experience, the material causes of our sensations, are not real. It seems to lead to a sceptical worry: how can I know that I don’t inhabit the matrix: a virtual or ideal reality, with an opaque causal ground? Both Berkeley’s immaterialist idealism and Kant’s empirical realism offer ways out of the matrix. But Kant’s solution does what Berkeley’s cannot: it vindicates the everyday world in which we determine the sequence of our thoughts in time by means of mind-independent objects and events.