I am because I say I am. If I'm not conscious and someone says I am, then I am. BUT if someone says "I'm not" and someone else says, "I am", the one that confirms my existence wins. Why? For me, there's no distinction between "imagination" and "reality" as the processes in our brains are real, measurable things in themselves and are part of the environment in which they find themselves. NOT seeing something that you say is real doesn't make it "not real". People might laugh, but that's a social thing, not a reality thing.