You're right, I think "authentic" was the incorrect word to use. I meant the idea of 2 Tim being a non-correspondence letter of Paul's, replying to issues brought up by Timothy as being history accurate. I fully ascribe to the canonical authenticity of both letters.

Speculation is fun, but we can't use our wondering to evaluate authenticity. We know there were other letters written by Paul to the Corinthians, but we don't have them. Even so, that doesn't denigrate the authenticity of the ones we have. So also with Timothy. If he wrote back to Paul between 1 Tim and 2 Tim, and yet we don't have that letter, it doesn't negate the authenticity of 1 & 2 Tim. It would change, however, our perception of 2 Tim as an independent letter or a response to something Timothy said.

Thanks for the help! All of these make sense, except I would think that, if authentic, there may be a letter from Timothy between our first and second letters to him.

Ha! I'm not sure there's a "general consensus" about anything regarding the NT! There are so many false scholars, fake information, bogus views, and untrained Christians, it's the Wild West out there. But that doesn't mean there isn't good scholarship in places, and that some individuals have a great command of the Word.

Here's the deal:
[list][*] 1 & 2 Corinthians: Correspondence about an issue
[*] Galatians: Certainly thematic ("It is for freedom the Christ has set us free"), but not a response to correspondence\
[*] Ephesians and Colossians: Paul is addressing theological issues (What God has done in and through Christ for us), but they're not correspondence as replies to an issue.
[*] Philippians: Probably correspondence replying to an issue, as you've said.
[*] 1 & 2 Thes: Yes, replying to an issue.
[*] 1 & 2 Tim: No. These are thought to be pastoral letters to his friend, Timothy (though some feel these, and esp. 2 Tim., were not written by Paul).
[*] Titus: Pastoral letter, not replying to an issue.
[*] Philemon: Paul writing a letter to his friend regarding the slave Onesimus.[/list]

I have read that 1 and 2 Corrinthians, Philippians, 1 and 2 Thesselonians are Paul's side of a correspondence. They are replies to letters addressed to Paul which we no longer have. Is there a general concensus as to how much of the NT are replies to an issue and which begin an issue?