Ordinary people won t be perplexed They know by symmetry that switching is OK but a waste of time if you don t open your envelope They don t really understand probability calculations anyway so they know there is something wrong with the argument but don t care what Regarding Smullyan s version they also know the answer it doesn t matter whether you switch or not so they know which argument of Smullyan s is correct As writer after writer has stated the problem of both original TEP and of TEP without probability is using the same symbol original or the same words Smullyan to denote two different things It s a stupid problem and has a simple resolution Well and if we are allowed to look in our envelope then everything is different But no longer very interesting for laypersons It turns out to be a fact of life that there are theoretical situations but I can simulate them on a computer for you they are not that theoretical where according to conditional expectation value you should switch whatever OK and this is just a fact about a random variable with infinite expectation value if I give you X you ll always be disappointed compared to its expectation But to get its expectation I would have to give you the average of millions and millions of copies of X Eventually the average will be so large that you ll prefer the swap whatever the value of the X I gave you first Then there are all kinds of nice calculations about whether or not you should switch given a prior distribution of X and there are cute things about what to do if you don t want to trust a prior then you should randomize It s all rather technical isn t it Only interesting for specialists By the way this is not theoretical since I can approximate a distribution with infinite expectation with one with very very very large finite expectation I can create approximately the same paradox without actually using infinite values Syverson does that It s very technical and hardly interesting for ordinary folk