Patterson: If Thomas were dependent upon the synoptic gospels, it would be possible to detect in the case of every Thomas-synoptic parallel the same tradition-historical development behind both the Thomas version of the saying and one or more of the synoptic versions. That is, Thomas’ author/editor, in taking up the synoptic version, would have inherited all of the accumulated tradition-historical baggage owned by the synoptic text, and then added to it his or her own redactional twist. This is not the case.
Rather than reflecting the same tradition-historical development that stands behind their synoptic counterparts, these Thomas sayings seem to be the product of a tradition-history which, though exhibiting the same tendencies operative within the synoptic tradition, is in its own specific details quite unique. This means, of course, that these sayings are not dependent upon their synoptic counterparts, but rather derive from a parallel and separate tradition.