is insufficient to prove thus much, and in the case of all other variants, this method so presents and limits the possible genealogical antecedents of the existing combinations of documentary evidence as to supply presumptions in favour of one variant against another varying from what amounts under favourable circumstances to practically absolute certainty down to complete equipoise.
80. So far as genealogical relations are discovered with perfect certainty, the textual results which follow from them are perfectly certain too, being directly involved in historical facts; and any apparent presumptions against them suggested by other methods are mere guesses against knowledge. But the inequalities and occasional ambiguities in the evidence for the genealogical relations frequently admit of more than one interpretation, and this greater or less substitution of probability for certainty respecting the documentary history reduces the textual verdict to a presumption, stronger or weaker as the case may be. Genealogical presumptions ought however to take precedence of other presumptions, partly because their immediate basis is in itself historical not speculative, and the subject-matter of all textual criticism is historical, partly because the generalisations by which that historical basis is ascertained involve less chance of error than the analogous generalisations required for any kind of Internal Evidence.
81. The only safe order of procedure therefore is to start with the reading suggested by a strong genealogical presumption, if such there be; and then enquire whether the considerations suggested by other kinds of evidence agree with it, and if not, whether they are clear and strong enough to affect the prima facie claim of higher attestation. If they appear so to be, a
