An armchair philosopher once had the following dream.
First Plato appeared, and the armchair philosopher said to him, "Could you give me a 15 minute capsule sketch of your entire philosophy?" To the armchair philosopher's surprise, Plato gave him an excellent exposition in which he compressed an enormous amount of material into a mere 15 minutes. But then the armchair philosopher raised a certain objection which Plato couldn't answer. Confounded, Plato disappeared.
Then Aristotle appeared. The same thing happened again, and the armchair philosopher's objection to Aristotle was the same as his objection to Plato. Aristotle also couldn't answer it and disappeared.
Then all the famous philosophers of history appeared one by one and our armchair philosopher refuted every one of them with the same objection.
After the last philosopher vanished, our armchair philosopher said to himself, "I know I'm asleep and dreaming all this. Yet I've found a universal refutation for all philosophical systems! Tomorrow when I wake up, I will probably have forgotten it, and the world will really miss something!" With an iron effort, the armchair philosopher forced himself to wake up, rush over to his desk, and write down his universal refutation. Then he jumped back into bed with a sigh of relief.
The next morning when he awoke, he went over to the desk to see what he had written. It was, "You are NOT going with that. Oh, wow. You ARE. That's just scary and speaks volumes on where you are coming from. Why are you even attempting to convince anyone of anything?!"