AnswerThirteen epistles have been attributed to Paul. Hebrews was also at one stage attributed to him, but that is clearly not the case, so we can say 'definitely', not 'probably' not written by Paul. It was never attributed to him until late in the second century.
Of the Pauline epistles, the Pastorals are almost unanimously regarded by critical scholars as not written by Paul - 1 Timothy, 2 Timothy and Titus.
The majority of critical scholars also say that Ephesians, Colossians and 2 Thessalonians were not written by Paul.
Many liberal Christian scholars now accept only Romans, 1 Corinthians, 2 Corinthians, Philemon, Galatians, Philippians and 1 Thessalonians as genuine. However, A.Q. Morton has cast some doubt on 1 Thessalonians and Philippians, because a computer analysis shows that they do not share the same dictation or writing style as the others.