internal, for believing that the first nine MSS were all copied directly or indirectly from the tenth MS, and derived nothing from any document independent of the tenth. He will then know that all their variations from the tenth can be only corruptions (successful cursory emendations of scribes being left out of account), and that for documentary evidence he has only to follow the tenth. Apart therefore from corruptions in the tenth, for the detection of which he can obviously have no documentary evidence, his text will at once be safe and true.
52. If however the result of the second supposed editor's study is to find that all the nine MSS were derived not from the tenth but from another lost MS, his ten documents resolve themselves virtually into two witnesses; the tenth MS, which he can know directly and completely, and the lost MS, which he must restore through the readings of its nine descendants, exactly and by simple transcription where they agree, approximately and by critical processes where they disagree. After these processes some few variations among the nine may doubtless be left in uncertainty, but the greater part will have been cleared away, leaving the text of the lost MS (with these definite exceptions) as certain as if it were accessible to the eyes. Where the two ultimate witnesses agree, the text will be as certain as the extant documents can make it; more certain than if the nine MSS had been derived from the tenth, because going back to an earlier link of transmission, the common source of the two witnesses. This common source may indeed be of any date not later than the earliest of the MSS, and accordingly separated from the autograph by any number of transcriptions, so that its text may vary from absolute purity to any amount of corruption: but as conjecture is the sole possible
