A Treatise Concerning the Principles of Human Knowledge

Irish philosopher and Anglican Bishop George Berkeley (1685-1753) wrote A Treatise Concerning the Principles of Human Knowledge in 1710. The short work expounds Berkeley’s philosophy of immaterialism, a form of empiricism asserting that nothing exists outside of a mind’s perception of it. Objects, therefore, are not things, but ideas. Berkeley’s philosophy critiques that of contemporary empiricists John Locke and David Hume, who contended that the mind can perceive the material world in abstract and that matter exists independent of a perceiving mind.

In Berkeley’s philosophy, a thing in the material world can never be understood in abstract terms because humans can only refer to their prior knowledge of the thing that they are perceiving. Empiricists believe that all knowledge comes through sensory experiences, and Berkeley takes this idea a step further to assert that when we perceive something, we are actually perceiving our own ideas about that thing. In his Treatise, Berkeley replaces the word “thing” with “idea” to be clear about the nature of its being. He asserts that first, human minds sense something—an object’s pleasant or unpleasant odor, its soft or prickly surface, its large or small size, and square or round shape.