solipsism

/ˈsɒl.ɪp.sɪz.əm/

noun

  1. (Philosophy) The view or theory that the self is all that can be known to exist, or that only one's own mind and conscious states are sure to exist. "Descartes contemplated methodological doubt that touched on solipsism before formulating his famous cogito principle."
  2. Extreme egocentricity or self-absorption, regarding oneself as the central and sole reference point of reality.