There was a three-page version of this joke in all variations in a Mad Magazine. Too bad it's probably not even in the deep web not in the web at all.

"A might be the reason for symptom X, then we have to take into account both the probability that X caused A"

I think you have accidentally swapped some variables there

Try privately arguing with a holocaust denier or a moon hoaxer. The ones I argued with seem to be more arrogant and more hostile the more they knew that they no third party is observing the "argument"

Like Karl Pilkington?

I stopped smoking after I learned about the Singularity and Aubrey de Grey. I don't have any really good data on what healthy food is but I think I am doing alright. I have also singed up to a Gym recently. However I don't think I can sign up to cryogenics in Germany.

I am a huge fan of Philip K. Dick. I don't usually read much fiction or even science fiction, but PKD has always fascinated me. Stanislav Lem is also great.

China also springs to mind. I have listened to documentary about the Chinese empire and distinctly remember how advanced yet stagnant it seemed. At the time my explanation was authoritarianism.

I suggest you read this

http://screwloosechange.blogspot.com/2008/04/griffin-and-barrett-suggest-olsons-were.html

Seems to be related to David Deutsch - A new way to explain explanation

the German name for Cologne is Köln