John Locke,
An Essay Concerning Human Understanding…
“ Knowledge, say you, is only the perception of the agreement or disagreement of our own ideas : but who knows what those ideas may be ? Is there anything so extravagant as the imaginations of men’s brains ? Where is the head that has no chimeras in it ? Or if there be a sober and a wise man, what difference will there be, by your rules, between his knowledge and that of the most extravagant fancy in the world ? They both have their ideas, and perceive their agreement and disagreement one with another. ”
