Full Idea
How matter should operate on a spirit, or produce any idea in it, is what no philosopher will pretend to explain; it is therefore evident there can be no use of matter in natural philosophy.
Gist of Idea
No one can explain how matter affects mind, so matter is redundant in philosophy
Source
George Berkeley (The Principles of Human Knowledge [1710], §50)
Book Reference
Berkeley,George: 'The Principles of Human Knowledge etc.', ed/tr. Warnock,G.J. [Fontana 1962], p.89
A Reaction
An intriguing argument for idealism, which starts in Cartesian dualism, but then discards the physical world because of the notorious interaction problem. Of course, if he had thought that matter and spirit were one (Spinoza) the problem vanishes.