I will try my best to explain this paradox. This is a paradox only if you act like a computer. So what do I mean by that? This problem simply means, that if yo

I will try my best to explain this paradox. This is a paradox only if you act like a computer. So what do I mean by that? This problem simply means, that if you selected an envelope, and you know that there is a chance that the other envelope will have higher value than then one you selected, then by probability, you could conclude that you are better off swapping to the other envelope. However, the paradox starts after you switch envelope because now you can start this all over again and think, hey, even though I just swapped, but it is still possible that the other envelope has value higher than the one I just selected! To explain it in mathematical terms, when the value of the currently selected envelope is Z, the expected value of the other envelope will always be Z/2 * 0.5 + 2Z * 0.5 = 5/4Z higher than the one you selected. The trick is to think procedurally, instead of trying to be realistic. In other words, it is always statistically possible that the other envelope has higher value than the one you selected, therefore you should always swap.