instrument for detecting or correcting whatever errors it may contain, this common source is the only original with which any of the methods of criticism now under discussion have any concern. Where the two ultimate witnesses differ, the genealogical method ceases to be applicable, and a comparison of the intrinsic general character of the two texts becomes the only resource.
53. The relations of descent between existing documents are rarely so simple as in the case supposed. To carry the supposition only one step further, the nine MSS might have been found to fall into two sets, five descended from one lost ancestor and four from another: and then the question would have arisen whether any two of the three authorities had a common origin not shared by the third. If it were ascertained that they had, the readings in which they agreed against the third would have no greater probability than the rival readings of the third, except so far as their common ancestor was found to have higher claims to authority as a single document than the third as a single document. If on the other hand the nine could not be traced to less than two originals, a certain much diminished numerical authority would still remain to them. Since however all presumptions from numerical superiority, even among documents known to be all absolutely independent, that is, derived from the autograph each by a separate line of descent, are liable to be falsified by different lengths and different conditions of transmission, the practical value of the numerical authority of the two supposed witnesses against the third could not be estimated till it had been brought into comparison with the results yielded by the Internal Evidence of all three witnesses.
