Idealism

Berkeley

The 18th-century philosopher George Berkeley is probably the most famous idealist in the history of Western philosophy. Berkeley believed in the existence of only two kinds of thing: minds and ideas. Ideas are dependent on minds for their existence: For an idea to exist is for it to be perceived by some mind. Although Berkeley denied the existence of material objects, understood as mind-independent entities, he claimed to accept the commonsense view that there are ordinary objects, such as tables, chairs, rocks, and planets. However, for Berkeley, such objects, which he was happy to call “physical” objects, are entirely constituted of ideas. A red, juicy apple is composed of the red idea we perceive when we look at it, the idea of solidity we perceive when we touch it, and the idea of juiciness we perceive when we bite into it (note that Berkeley, in keeping with the empiricist tradition of his time, uses the word idea to mean something like “a mental thing which is the immediate object of sensory perception”).

Part of our commonsense understanding of physical objects is that they remain in existence even when no one is around to look at them. Berkeley had two strategies for accommodating this ordinary belief. The first strategy is that the apple exists by virtue of the fact that if someone were to look in its direction, she or he would perceive the visual ideas that make it up (and if she were to touch it, she would perceive the idea of solidity that makes it up, and if he were to bite into it, he would perceive the idea of juiciness which makes it up, etc.). The second strategy is that the apple exists by virtue of the fact that, even in the absence of human perceivers, God is permanently perceiving the apple: seeing its redness, feeling its hardness, tasting its juiciness.

It is crucial in understanding Berkeley's view to see him in relation to John Locke, the British empiricist who came before Berkeley and whose life overlapped with Berkeley's. Locke claimed that the immediate objects of perception are sensory ideas (call this claim A), although he also believed that we indirectly perceive mind-independent material objects. Locke argued that some qualities of objects, such as color and taste, are dependent for their existence on the mind, on the grounds that our ideas of these qualities vary according to the perspective of the perceiver (call this argument B). However, he also claimed that other properties, such as solidity and extension, are mind independent.

[Page 398]Berkeley took claim A and argument B to what many believe to be their logical conclusion. If the only things we immediately perceive are ideas, it is difficult to see how we could ever have evidence for the existence of mind-independent objects. If the fact that ideas of color and taste vary depending on the perspective of the perceiver gives us grounds to think that color and taste are mind dependent, then we also have grounds for thinking that solidity and extension are mind dependent, as the ideas of these qualities also vary depending on the perspective of the perceiver (the idea of a object's shape varies depending on the angle from which we look at it).

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