I would say we are correct to ontologically wonder sometimes, as we all do, whether we are simply a figment of our own imagination. I contend that we self-create. Instead of the Cartesian Cogito, ergo sum--"I think, therefore I am"--which posits an Ego, an I who is a priori (presupposed), I would say, Placebo, ergo sum--I hallucinate myself into being. The perennial philosophical problem, of course, is just who is this "I" who we all think exists?
Stay tuned: I'm working on it! Ha! Meanwhile, "I" "am" here.