Solipsism

Solipsism is the philosophical belief that the only entity that can be conclusively known to exist is oneself, more specifically, one's mind. It is important to note that solipsism does not deny the existence of the universe as we perceive it; it simply states that it cannot be proven to exist, since we cannot prove that the evidence given by our senses is not an illusion.

Within this general definition of solipsism, there are three subtypes:

• Metaphysical solipsism: The idea that one's mind is the only reality, and that the "external" world is merely a projection and representation of one's mind.
• Epistemological solipsism: The idea that the existence of the mind is the only thing that can be conclusively known, and all things external to the mind are unknowable.
• Methodological solipsism: The idea that since the self is the only thing that can be conclusively known, then in order to be valid, philosophical belief must be grounded in the individual self and its states.

Solipsism is similar to subjectivism.

Failure of solipsism

Solipsism fails on the unavoidable concrete experience of the reality of other minds through the evidence of social interactions, parents, family members and community, the phenomena of language and communication, unexpected occurrences and accident, conflict, arguments, unavoidable environmental and social irritations, involuntary distractions, differing states of physical health, sensory responses not intended or expected, exposure to surprising new ideas, discovery of limitations of understanding, laws of logic, correction of previously unnoticed errors in reasoning, discovery of things previously inconceivable but true and facts previously unknown to oneself, episodes of dreamless sleep and unconsciousness followed by conscious awareness, and the inescapable conclusion finally that one's own mind is not self-subsistent or self-caused but must have had an unremembered beginning within a universe that one did not create or generate or maintain and has physical laws that cannot be fundamentally altered according to one's will.
Ergo: the objective existence of the orderly universe as we perceive it can be conclusively proven, since we can prove that the evidence given by our senses is not an illusion.

Compare Natural Law, Falsifiability and Epistemology.