Berkeley's Of the Principles of Human Knowledge
- Berkeley (1658-1753) begins with the claim that there
are ideas, and these are either
- Sense impressions
- Reflections on the passions or other mental events
- Memories or imaginings
- There is also a perceiver, and this I call myself, or a
soul, or a mind.
- Ideas require a mind (the perceiver)
- To exist is to be perceived: "esse is percipi"
- Supposition of any addition notion of existence is
contradictory: it is to suppose that there is an unperceived
- Why have we supposed imperceptible existences? Perhaps
some notion of abstraction.
- Since everything requires mind to exist, "there is not
any other substance than spirit, or that which perceives"
(remember, "substance" is a technical term for being (ousia)
and means a thing that can exist independently).
- Berkeley also rejects the idea of primary versus
secondary qualities (a view of Locke's).
- According to Locke, primary qualities exist in
the thing, and secondary qualities are projected onto
a thing by us.
- Berkeley sees in this the underlying idea of
"matter" as a thing that has no properties of its own
but holds other properties.
- But, pure matter is a stuff without any sensible
properties. It is impossible to conceive of this
imperceptible stuff that underlies objects but itself
has not real properties of its own.
- Also, supposed primary qualities like extension
are as much a perceptible thing as are heat. They are
also various by the perceiver, since for example we
use different measures of extension.
- Berkeley attacks at this point the idea of matter and
- The idea of matter is just the idea of being in
general. But this does not prove that matter is a
- Nor do we even need to suppose that bodies are
separate from perception.
- "The supposition of external bodies is not
necessary for the producing our ideas"
- Furthermore, positing bodies explains nothing,
since we have no theory of why bodies cause sensations
or other ideas.
- If there were bodies (in this usual sense of the
word), it would be impossible to know!
- This is Berkeley's idealism, which posits the world is
ideas - but it is empiricism, not a form of rationalism (as
was the idealism of Plato).
- Berkeley does conclude that there must be a source of
many ideas other than myself
- I have will over some ideas
- But I have no will over many ideas
- There must be another will that produces
- Similarly, there are other special features of
- Some ideas are stronger than those
produced by my will
- These ideas have regularity; this allows for
- Some ideas are the ideas had by God.
- God also is viewing the world, and creating and maintaining
these stronger, consistent ideas (over which I have no control).