Therefore, Samkhya chooses representational realism over epistemological solipsism. An extreme version of this idealism can exist in the philosophical notion of solipsism. On this scale, solipsism can be classed as idealism. Methodological solipsism is an agnostic variant of solipsism. Solipsism is a form of logical minimalism. Metaphysical solipsism is a variety of solipsism. The concept of the Self in the philosophy of Advaita could be interpreted as solipsism. The simplest use of brain-in-a-vat scenarios is as an argument for philosophical skepticism and solipsism. Solipsism is the philosophical idea that only one's own mind is sure to exist. Critics of solipsism find this somewhat implausible. A similar skepticism concerning the concrete world can be found in solipsism. Denial of material existence, in itself, does not constitute solipsism. In the history of philosophy, solipsism has served as a skeptical hypothesis. Periods of extended isolation may predispose people to solipsism syndrome. Solipsism is also skeptical of sense-data.