For nothing is more certain than that no man ever came out of himself in order to identify himself directly with things which are different from him; but everything of which he has certain, and therefore immediate, knowledge lies within his own consciousness.
 Arthur Schopenhauer, The World as Will and Representation (1819). copy citation

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Author Arthur Schopenhauer
Source The World as Will and Representation
Topic consciousness lie
Date 1819
Language English
Reference
Note Translated by R. B. Haldane and J. Kemp
Weblink http://www.gutenberg.org/files/40097/40097-h/40097-h.html

Context

“But his correct and profound insight into this truth really constitutes Berkeley's whole philosophy; in it he had exhausted himself. Thus true philosophy must always be idealistic; indeed, it must be so in order to be merely honest. For nothing is more certain than that no man ever came out of himself in order to identify himself directly with things which are different from him; but everything of which he has certain, and therefore immediate, knowledge lies within his own consciousness. Beyond this consciousness, therefore, there can be no immediate certainty; but the first principles of a science must have such certainty. For the empirical standpoint of the other sciences it is quite right to assume the objective world as something absolutely given;” source