I record a lot of people that may do a great take and mess up in a few spots on take. Comping is great and is the reason that I bought the software, but I was wondering does anyone know if there's a way that previously recorded material in the same channel can be heard simultaneously while recording? Is it possible or not? It would be great for an artist especially someone that is freestyling a project to be able to go back to hear there previous recorded sound and pick up where they messed up that I've cut. Thanks 

Right-click the track in question and make a duplicate track with the same effects chain etc, but with no "Events" i.e. clips. Have them record/punch in to their heart's content on the duplicate track, and then drop the best take in afterwards!

With something like this, especially on critical elements like a lead vocal or solo or something, I usually save an archive copy of the full, every-take punch-in track as well, using the Archive feature and then sending it to a folder on the project called Archive. That way you can always go back and fish for something better if you, say, decide that a certain phrase or note or whatever isn't really doing it for you at a later date.

Thanks that's I've done it the duplicate way and manual way

Maybe I'm missing something in what you're looking for, but you can make a timeline selection to punch in wherever you need to, then in the Preferences under Project/Record, make sure "Mute Previous Takes" is unchecked.  That will allow you to remain in Comping mode while still hearing previous takes.