What if this is a possibility?

[leader of mortals]

What if it is possible that I am the only person in the world that I see, and everyone around me is only a halucination made up by my mind. All the previous advancements in technology are there because I imagined them to be. This computer is not really here, I am so mad that I feel this computer, and I see this computer, and I see the words on this computer.

Ive had the same thought but my conclusion was what if im actually retarded and percieve the world as normal, so where I think Im typing to people online im actually banging my fingers on a scrabble board in the middle of a family game and when i think im having a normal conversation im actually yelling and slurring while flinging my poo.

Along this same line of thought, I've often wondered if I could ever truly know if what I experience is all a dream or my waking world. And if it was a dream, that at any moment I could wake up and my life would be something far from what I thought it was.

Yes, and, fairly related, how do you know if everything you see is what others see? Maybe for some people, what you percieve as Dark is what they see as Light, and of course there would not be any way to know because they would always learn that thier Dark is Dark and thier Light is Light. Same for colors, maybe your Blue is thier Red, but they were taught that Blue is Blue, so they learned from what they saw.