It is indeed an Opinion strangely prevailing amongst Men, that Houses, Mountains, Rivers, and in a word all sensible Objects have an Existence Natural or Real, distinct from their being perceived by the Understanding. But with how great an Assurance and Acquiescence soever this Principle may be entertained in the World; yet whoever shall find in his Heart to call it in Question, may, if I mistake not, perceive it to involve a manifest Contradiction. For what are the forementioned Objects but the things we perceive by Sense, and what do we perceive besides our own Ideas or Sensations; and is it not plainly repugnant that any one of these or any Combination of them should exist unperceived?
Some Truths there are so near and obvious to the Mind, that a Man need only open his Eyes to see them. Such I take this Important one to be, to wit, that all the Choir of Heaven and Furniture of the Earth, in a word all those Bodies which compose the mighty Frame of the World, have not any Subsistence without a Mind.
George Berkeley – A Treatise Concerning the Principles of Human Knowledge