The fact that the scribe of Β was a 'corrector' of א shews that the two MSS were written in the same generation, probably in the same place: but as regards the text it has no independent force, though it would have to be taken into account if the internal evidence were to point to the use of a common exemplar. On the other hand a strong presumption to the contrary is created by remarkable differences in the order of the books, the divisions into sections, and other externals.
289. Turning then to the internal evidence afforded by the texts themselves, we are at once confronted by the question,—How can we know that any two MSS are both derived from a common parent or near ancestor? Certainly not, as is often assumed, from the bare fact that they have many readings in common, with or without the support of other documents. What is absolutely certain in these cases is that those readings have some common ancestor, coincidences in independent error being always excepted; and it is morally certain that the same ancestor supplied more or less of the rest of the text. But this ancestor may have been at any distance from the MSS, near or remote, back to the autograph itself inclusive. That this is no exaggeration will be seen at once by following the course of transmission downwards instead of upwards. Whenever an original reading has disappeared from all representatives of all originally independent lines of transmission except two, and each of these two lines has either but a single extant representative or has itself lost the true reading in all its extant representatives but one, the resulting distribution is precisely as supposed, two MSS against the rest: and this is a common case in many texts. To what stage in the transmission the common ancestor implied by the identical
