solipsism (noun)

1. Why did the solipsist go to the party? Because he was the only person he knew who would be there!

2. In the science fiction novel, the protagonist discovers that the entire universe is a result of his own solipsism.

3. According to Greek mythology, Narcissus was so obsessed with his own reflection that he exemplified solipsism.

4. During the Renaissance, the idea of solipsism was challenged by the emergence of humanism and a renewed interest in the exploration of the external world.