I particularly like Judy's discussion of the dependence-independence problem between Thomas and the Synoptics, and how she thinks that this may relate to "non-canonical unease" - gosh is this beginning to sound like an illness :)?
Judy Redman says:
I think, however, that the primary reason that non-canonical texts make us uneasy (or at least those of us who have grown up in a Christian church, no matter what we believe now) is that they have generally been labelled “heresy” by the mainstream church. Heresy, as we all know, is devised by Satan to lead the faithful away from the one true faith and into eternal damnation, so these texts are dangerous.
In fact, this is not how I conceptualise heresy at an intellectual level, but the indoctrination of decades dwells deep within my psyche and looking at “heresy” makes me uneasy (although it clearly doesn’t stop me). Coming to non-canonical texts with an open mind means that you might end up being convinced by what they say and thus end up outside orthodoxy. Which is uncomfortable. You might even end up believing that you should try to convey your new understandings to the orthodox church, which has the potential to be very uncomfortable indeed.
This, I think, is why there was (and still is to a certain extent) such an interest in looking at whether or not Thomas is dependent on the synoptics, and in using dependent/independent language in the first place, rather than talking about whether Thomas might have used one of the synoptics as a source, as we do when talking about the relationship between Mark, Matthew and Luke. If we can show “dependency”, then we feel that we are in a stronger position to argue that it is safe to ignore anything in Thomas that comes into conflict with orthodox Christian doctrine. If it’s not dependent, then we may have “authentic words of Jesus”, which makes us uneasy, because we may have to think about changing long-accepted doctrine/theology.