So, this has me thinking: how does one go about deciding authorship? When one looks at the scholarship, it's a morass. Paul is just assumed to have written the undisputed Pauline epistles, without question. If Acts' presentation of Paul are thought to differ from how Paul is presented in these epistles, Acts is judged without question to be in error. If the presentation of Paul in the Pastoral Pauline epistles is thought to differ from that in Acts, then the Pastoral Epistles are judged to be in error without question. If the presentation of James or Peter in Acts or the undisputed Pauline epistles differs from that found in the letters of James or 1 or 2 Peter, James or 1 or 2 Peter are judged to be in error without question. There is an unspoken hierarchy: data from undisputed Pauline epistles are supposed without question; data from Acts is accepted where it does not conflict with data from undisputed epistles; data from other epistles, Pauline or Catholic, are accepted where it does not conflict with data from undisputed Pauline epistles or Acts. No attempt to justify this hierarchy of data is advanced; it is just tacitly assumed.
So, then, the question of how to establish authorship really becomes: how do we know that Paul wrote the undisputed epistles? Who can answer that? Very few, I suspect. But how we answer that, it must become the paradigm for answering the question of authorship of any other text. I would suggest that the following procedure is at work. It's very simple. We see that it is attributed to Paul, and find no compelling reason to think that to be in error. This judgment is not offered without data: the crucial datum in each case is the attribution. In most cases this will be a necessary condition, but due to the phenomenon of pseudepigraphy in no case will it probably be sufficient. Thus to this positive test we must add the negative test of compelling reason to judge against the attribution.
The question thus becomes: what reason do we have to say that Paul did not write this? James? Peter? Mark? Matthew? Etc. In each case, the nature of the case will be different, and must be argued from the particularity of the data. Of course, in many cases the particularity of the data will be similar, and some data even will recur from letter to letter (such as with the details of Paul's life, which will recur throughout deliberations on the thirteen canonical Pauline epistles as well as extra-canonical texts attributed to Paul). There will be cases in which the answer is very obvious, in either direction; there will be cases in which that is less the case. Chronology will be related to this in a complex fashion. Sometimes it might exclude the traditional authorship. If a letter clearly references an event that occurred after the author's known time of death, then the traditional authorship must be in error. Sometimes the question of authorship will aid in answering chronological questions, by establishing that the text was likely written during the traditional author's lifetime. The putative authorship establishes an initial time frame in which to look. If we judge that James, brother of Jesus, wrote the Epistle of James, then we can hardly date the letter later than 62, the year in which (on the basis of Josephus) we know that he died; if Peter wrote 1 Peter, the letter cannot date likely date any later than 68; etc. In most cases, the lower end of possibilities is circumscribed by references to Jesus' life, ministry, or death, making a date earlier than c. 30 impossible.
Authorship and date turn out to be indissolubly linked.