Berkeley: Life and Main Philosophical Ideas

Biographical Background

George Berkeley lived from 1685 to 1753. He was an Irish philosopher and Anglican bishop. Educated at Trinity College Dublin, he wrote major philosophical works while still young, including An Essay Towards a New Theory of Vision, A Treatise Concerning the Principles of Human Knowledge, and Three Dialogues between Hylas and Philonous.

Berkeley accepted empiricism but believed Locke's theory of material substance led toward skepticism and atheism. He tried to defend common sense and religion through a more radical empiricism.

Philosophical Thought

Berkeley's famous principle is esse est percipi: to be is to be perceived. We directly experience ideas: colors, sounds, shapes, hardness, motion, and so on. We never experience an unperceived material substance standing behind these ideas. Matter, as an unknowable support of qualities, is therefore an unnecessary abstraction.

Berkeley also criticized abstract ideas. We can use general words, but we do not possess impossible abstract images such as a triangle that is neither equilateral, nor isosceles, nor scalene. Philosophical confusion often comes from mistaking words for ideas.

He did not think the world is a private fantasy. Sensory ideas are vivid, orderly, stable, and not controlled by our will. Their order is guaranteed by God, who perceives all things and presents ideas to finite minds according to laws.

Berkeley rejected Locke's distinction between primary and secondary qualities. Shape and extension are just as dependent on perception as color and sound. We cannot conceive extension without some visual or tactile experience.

Berkeley's importance lies in pushing empiricism to its limit. If all knowledge begins in experience, what justification is there for a mind-independent material substance beyond experience? His answer reshaped debates about perception, idealism, and skepticism.