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Ah this is a different version of the problem. There are quite a few listed on the wikipedia page. I believe the version you are talking about is just a simple

• baobabKoodaa 4y ago
  > Ah this is a different version of the problem. There are quite a few listed on the wikipedia page. The vast majority of the Wikipedia article concerns variants that do not involve opening the first envelope. The first definition of the problem states "before inspecting it". The first section, "Introduction", also describes the problem similarly: "before they open it". This section - which defines the problem - does not introduce any variants which involve opening the first envelope. The next section, "Simple resolution", describes a resolution to the variant described in the introduction (where the first envelope is not opened). The next section, "Other simple resolutions", also discusses the same variant (where the first envelope is not opened). At the end of this section there is a remark "We could actually open our envelope before deciding on switching or not and the above formula would still give us the correct expected return", but that is the extent to which the first-envelope-is-opened variant is discussed there. I could go on. My point is that the discussion very clearly revolves around the variant where the first envelope is not opened, and you have to go down a pretty deep rabbit hole in order to find a variant where the first envelope is opened. > I believe the version you are talking about is just a simple equivocation. Yes, just a simple equivocation, with a Wikipedia page that could be printed as a book. Does anything strike you as odd about that?