You see that I post this. This doesn't prove I'm exactly what you think. But you see that their is a post supposedly by me. I cannot just not exist, else there would be no post. Even if this is all a dream in your head, I still exist there because I exist through this post. No matter how you tell me that I don't exist in reality, I do in yours. You see, hear, or message me. I exist in some way shape or form, even if it isn't the expected one. Therefore, I exist in someway.