First, Know Thyself To Be A True Fact

Fact is held self-evident, per consensual acceptance and incessantly observed existence.

Truth is ideal and so held in faith, per cognitive agency.

Solipsism is the “I think therefore I am” logic; in that it’s the knowledge one’s self is real but all else is questionable. Etymologically, solipsism means, “alone self”; or the state of being the only self.

Thus, you yourself are a true fact only unto thyself.