solipsism, epistemological 1) the theory that one’s consciousness (self, mind) cannot know anything other than its own content. 2) one’s consciousness alone is the underlying justification for, and cause of, any knowledge of the existence or nonexistence of anything at all. Contrasted with objectivism (epistemology).

solipsism, metaphysical literally, “I myself only exist”; the theory that no reality exists other than one’s self. The self (mind, consciousness) constitutes the totality of existence. All things are creation of one’s consciousness at the moment one is conscious of them. Other things do not have any independent existence; they are states of, and are reducible to, one’s consciousness.

Source: Peter A. Angeles, The HarperCollins Dictionary of Philosophy.