George Berkeley

Western Philosophy
18th century philosophy

George Berkeley was a philosopher. His primary philosophical achievement was the advancement of a theory he called "immaterialism" (later referred to as "subjective idealism" by others). This theory, summed up in his dictum, "Esse est percipi" ("To be is to be perceived"), contends that individuals can only directly know sensations and ideas of objects, not abstractions such as "matter." His most widely-read works is A Treatise Concerning the Principles of Human Knowledge (1710).

Berkeley was born in Ireland and educated Trinity College, Dublin. His Treatise concerning the Principles of Human Knowledge served as an attack on the concept of materialism that was popular in his day. Briefly, materialism is the view that the only thing that can be truly proven to exist is matter. Fundamentally, all things are composed of material and all phenomena (including consciousness) are the result of material interactions; therefore, matter is the only substance: there is no such thing as mind, soul, or spirit.

As a young man, Berkeley theorized that individuals cannot know if an object is; they can only know if an object is perceived by a mind. He stated that individuals cannot think or talk about an object's being, but rather think or talk about an object's being perceived by someone. That is, individuals cannot know any "real" object or matter "behind" the object as they perceive it, which "causes" their perceptions. He thus concluded that all that individuals know about an object is their perception of it.

This raises the question whether this perceived object is "objective" in the sense of being "the same" for fellow humans. In fact, is the concept of "other" human beings, beyond an individual's perception of them, valid? Berkeley argued that since an individual experiences other humans in the way they speak to him —something which is not originating from any activity of his own —and since he learns that their view of the world is consistent with his, he can believe in their existence and in the world being identical or similar for everyone.

According to Berkeley:

ð Any knowledge of the world is to be obtained only through direct perception.

ð Error comes about through thinking about what individuals perceive.

ð Knowledge of the world of people, things and actions around them may be purified and perfected merely by stripping away all thought, and with it language, from their pure perceptions.

Theologically, one consequence of Berkeley's views is that God must be present as an immediate cause of all our experiences. For instance, my perception of a tree is an idea that God's mind has produced in mine, and the tree continues to exist in the quadrangle when "nobody" is there, simply because God is an infinite mind that perceives all.

Over a century later Berkeley's thought experiment was summarized in a limerick by Ronald Knox and an anonymous reply:

There was a young man who said "God

Must find it exceedingly odd

To think that the tree

Should continue to be

When there's no one about in the quad."

"Dear Sir: Your astonishment's odd;

I am always about in the quad.

And that's why the tree

Will continue to be

Since observed by, Yours faithfully, God."

Berkeley is referred to as the father of idealism.

Comprehension Questions (To be answered in Complete Sentences on a separate sheet of paper):

1. Explain what is meant by the dictum: "To be is to be perceived."

2. Define materialism and state Berkeley’s argument against it.

3. Explain Berkeley’s theory of idealism.

4. Explain the humour of the limerick reproduced above as a criticism of Berkeley’s theory.

5. Evaluate Berkeley’s theory according to your own views (You’ll need to elaborate, eh?)

6. Explain how “Barkly” is relevant in the philosophical discussions between Mr. Digby and Mr. Palmer in Who Has Seen The Wind. Why would the author include mention of Berkeley’s theory of idealism?