:This solution is a simple conditional solution using Rosenthal's "proportionality principle" (which is really a consequence of Bayes' theorem).  The reason this isn't a "featured" conditional solution in the article is because Rosenthal's "proportionality principle" is not a well known principle presented in most probability textbooks - unlike using a decision tree or directly using Bayes' Theorem (which are both completely standard).  There are dozens (possibly hundreds) of sources that present conditional solutions to the MHP using a decision tree or Bayes' Theorem - and (AFAIK) only one using Rosenthal's "proportionality principle".   However, it is definitely conditional, and he's definitely in "Morgan's camp".