Editing Bayesianism (section)

==Explanation==
The speaker is misunderstanding {{w|Bayesian probability|Bayesian probability}}, an interpretation of probability as a measure of personal belief. He points out that one can make arbitrarily many (and in fact, infinitely many) competing theories to any given theory, and thus fallaciously concludes that this implies each theory has arbitrarily small probability (including, in this case, the undesirable theory that he will die). There are several fallacies here: First and foremost, he is assuming that his subjective probability actually reflects reality - approximately described by the concept of a {{w|Calibrated probability assessment|calibrated probability}}. The second fallacy is that all unknown options are equally likely - namely that each competing theory must take up some non-trivial fraction of the total probability. To see this is fallacious, consider the collection of hypotheses "In exactly x seconds, I will gain an invincibility cloak" for each positive real number x. Since there are uncountably many of these hypotheses, it is not possible for all of them to have non-zero probability. Lastly, it is not true that a Bayesian believes that every event has positive probability - it simply means that if an event that they a priori believe to be impossible happens, it would not change their belief about this event.

A similar concept to this is expressed in the {{w|Simulation hypothesis|Simulation hypothesis}}, although there whether it is fallacious is highly disputed.