Solipsism
(Listeni/ˈsɒlᵻpsɪzəm/; from Latin solus, meaning "alone", and ipse, meaning "self")[1] is the philosophical idea that only one's own mind is sure to exist. As an epistemological position, solipsism holds that knowledge of anything outside one's own mind is unsure; the external world and other minds cannot be known and might not exist outside of the mind. wiki
Interesting thought