Internet is the proof that you're not in coma. You have endless supply of information on any topic imaginable and there's no way you have all that stored inside your head
What if one's mind is making it all up as one goes through the dream, and inconsistencies are rationalized away as being the result of not remembering details?
But what if you are just imagining having endless supply of information, but you mind is able to actually visualize only porn, pictures of cats and arguing with other communists?