Second, there is internal evidence . Internal evidence has to do with the intrinsic likelihood of the various readings. The more difficult reading is to be preferred. Scribes are more likely to smooth things out than to rough them up. The shorter reading is to be preferred.
Scribes tend to add rather than subtract material.
When some readings parallel other biblical texts, the divergent reading is to be preferred. Again, scribes are more likely to harmonize sacred texts than to create discord among them.