The Wikipedia article about Wittgenstein says:
In Norway it was clear that Moore was expected to act as Wittgenstein's secretary, taking down his notes, with Wittgenstein falling into a rage when Moore got something wrong. When he returned to Cambridge, Moore asked the university to consider accepting Logik as sufficient for a bachelor's degree, but they refused, saying it wasn't formatted properly: no footnotes, no preface. Wittgenstein was furious, writing to Moore in May 1914: "If I am not worth your making an exception for me even in some STUPID details then I may as well go to Hell directly; and if I am worth it and you don't do it then—by God—you might go there."
Furthermore it says:
Despite this fame, he could not initially work at Cambridge as he did not have a degree, so he applied as an advanced undergraduate. Russell noted that his previous residency was sufficient to fulfill eligibility requirements for a PhD, and urged him to offer the Tractatus as his thesis. It was examined in 1929 by Russell and Moore; at the end of the thesis defence, Wittgenstein clapped the two examiners on the shoulder and said, "Don't worry, I know you'll never understand it." Moore wrote in the examiner's report: "I myself consider that this is a work of genius; but, even if I am completely mistaken and it is nothing of the sort, it is well above the standard required for the Ph.D. degree." Wittgenstein was appointed as a lecturer and was made a fellow of Trinity College.
How was it possible for Wittgenstein to get a PhD in philosophy without having a Bachelor's degree in philosophy? And how was it possible that his work satisfied requirements for a PhD but not for a Bachelor's degree?