How do we justify our knowledge of the external world?
Knowledge of the external world seems to be fallible in any case if we put the threshold of success at the highest level, namely 100% certainty. But this still raises a question: if we want to avoid complete skepticism, how can we be certain that our knowledge is at least likely to be true? In order to create a probability about the validity of our knowledge of the external world we need to start from perception. The problem is that we can be certain of the existence of perception but not the source of it (the matrix/the real world), and that is essential for the knowledge of the external world.
In order to calculate our probability we then need the number of possible events E and the one favourable event F we're looking for:
E = 2 possible events are external source or non-external source (matrix, hallucination, dream etc.)
F = 1 favourable event i.e. external source
P(F) = F/E = 1/2 = 50%
It seems to me that both possibilities are equally likely. Why should I believe one over the other? A lot of people answers this question by saying that the simulation hypothesis is too convoluted and not as simple as common sense realism. But Doesn't that depend on the context? For example: If the reality in which I'm simulated there's an infinite amount of simulations the hypothesis would not be that convoluted. If I have no access to the external reality how am I supposed to establish what is convoluted and what is not?
My question is: What makes external world realism more plausible?