One could just as easily argue against the Pauline authorship of the Pastorals as the Pauline authorship of Hebrews. To say that Paul could not have authored 1-2 Timothy and Titus because they differ from Paul's "known style" begs the question since the vocabulary and style of the Pastorals are excluded in the "overall style." The same logical fallacy occurs if anyone tries to determine "my" (Dave Black's) style from my academic writings and then applies it to my books written for lay people. Yet I am indisputably the author of all of these books.
In addition, if you're a proponent of Apollos or Barnabas as the author of Hebrews, how would you answer this question: "How does the style of Hebrews compare with the writings of Apollos or Barnabas?" That's obviously an absurd question to ask since nothing Apollos or Barnabas may have written has come down to us. On the other hand, the numerous affinities between Hebrews and the Paulines are apparent in every paragraph of the letter. No decision about authorship can and should be made without such a comparison. Indeed, one must study the letter in detail in order to determine its style and whether or not that style comports with the Paulines. When this is done objectively, I believe that a case can still be made for the Pauline authorship of Hebrews based on the letter's style, vocabulary, and diction.
