Knowledge is called empirical when it rests wholly or partly upon experience.
 Bertrand Russell, The Problems of Philosophy (1912). copy citation

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Author Bertrand Russell
Source The Problems of Philosophy
Topic experience rest
Date 1912
Language English
Reference
Note
Weblink http://www.gutenberg.org/files/5827/5827-h/5827-h.htm

Context

“When anything is known immediately, its existence is known by experience alone; when anything is proved to exist, without being known immediately, both experience and a priori principles must be required in the proof. Knowledge is called empirical when it rests wholly or partly upon experience. Thus all knowledge which asserts existence is empirical, and the only a priori knowledge concerning existence is hypothetical, giving connexions among things that exist or may exist, but not giving actual existence.” source