April DeConick poses this question on her blog and I thought, as someone who is studying a non-canonical text, I might have a go at answering it.
Several people have suggested that one of the reasons that the non-canonical texts make us uneasy is because there isn’t a centuries-long history of interpretation for us to fall back on, so we don’t know what they mean. I guess this may be true, but for me it’s an opportunity to look at text without any major preconceived ideas about its meaning. Of course, we don’t have available to us a huge range of other people’s interpretations, just the occasional writing of a Church Father indicating that the author has got it wrong in a big way. If you are among the earliest scholars of the text, you don’t know ahead of time which people you’re aligning yourself with and who you’re disagreeing with. This could make you very uneasy, because some of our colleagues are not exactly gracious when they disagree with you. 🙂
One thing that makes me uneasy about drawing conclusions from the extra-canonical texts is that we have so few copies of them. When you look at the number of copies of the canonical texts that are in existence and the differences between them, you realise just how difficult it is to make any definitive statements about a text when there are only one or two or a handful of copies in existence. You might have a very accurate version of the original text, or you might have a wild corruption and you have no way of knowing.
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.