Solipsism
From RationalWiki
Solipsism is the philosophical viewpoint that nothing can be proven beyond the existence of the self. Popularly identified with the phrase cogito ergo sum, solipsism holds that no perception felt by the mind can be regarded as truly verifiable, and so its existence is not certain. Hence, nothing outside the mind of the observer can be rationally confirmed.
Unlike the similar viewpoint of "subjectivism", solipsism goes beyond mere skepticism of objective reality and regards the existence of other minds, or observers, as being uncertain as well.
