I'm sure you are. I'm not. And I think we still need to do a lot of work to put textual criticism on a solid mathematical footing, the way that evolutionary theory has been.
The evidence against it is:
1. That א, (A), B, (C), (L), X, (Δ), 33, 131, and 157 omit it. A and C are here defective, but they leave no sufficient space for its insertion; L and Δ leave gaps, to notify some omission, which the copyist for some reason did not or dared not fill. Though found in D, E, F, G, H, K, M, S, V, T, Δ, Λ, Π, and numerous cursives, it is nevertheless obelized in some of the former as doubtful.
(8) The pericope adulterae. (a) Excursus on the genuineness of Jn 7:53-8:11. It is our duty to examine the various grounds on which this passage has been almost universally concluded to have formed no portion of the original Fourth Gospel; and then the internal grounds on which it has been rejected, and some of the speculations as to its origin and value. Doubts have beset the authenticity of the passage from the fourth and fifth centuries in the Eastern Church, both on external and internal grounds. The authority and practice of Augustine, Ambrose, and Jerome gave it a secure resting place till the criticism of Erasmus re-awakened doubt. Calvin expressed a more favourable opinion concerning it. Jansenius rejected it. Grotius considered it as an addition to John’s Gospel from the hand of Papias or one of his friends and fellow disciples of John. Wettstein, Semler, Griesbach, and Wegscheider seemed to leave for it no place in Scripture. Lachmann omitted it from his text. It has been condemned as spurious by the great bulk of modern critics, even of different schools and on somewhat different grounds. Some have rejected it as a spurious forgery (see Hengstenberg, in loc.); Keim derives much the same conclusion from its supposed teaching; Others (Scrivener) that, from its interruption of the narrative, it has no place here, but may be possibly regarded as an appendix to John’s Gospel, or a part of the later edition of that Gospel which contained Joh_21:1-25.
A very damaging note accompanies it in 1 (see Tregelles, who gives it at length). The following critical editors have either displaced it or entirely rejected it from this place in John’s Gospel, though many among them admit its virtual authenticity as a record of a genuine occurrence in the life of our Lord: Lachmann, Tregelles, Tischendorf, Alford, Lucke, Meyer, Godet, Milligan, Scrivener, Moulton, Westcott and Hort, the Revised Text, and even Weiss and Wordsworth.
Ancient versions, such as some of the Italic, AEgyptian, Old Syriac, Gothic, early manuscripts of the Peschito and Armenian versions, omit it. It was not read by Tertullian, Cyprian, Origen, Theodore of Mopsuesfia, Chrysostom, Cyril of Alexandria, and Theophylact, where it might have been expected. The defenders of its authenticity allege that Origen’s commentary and homilies are lacking or mutilated over the fifth, sixth, and seventh chapters. While this is true, Origen (’Tom.,’ 19.) points out the connection between Joh_7:40 and Joh_8:12 without making the faintest reference to this pericope. "No catenae as yet examined contain notes on any of these verses" (Westcott and Hort).
With the exception of the ’Apostolic Constitutions,’ the Greek writers and commentators are ignorant of it,
and there is no proof of its existence in any extant manuscript earlier than the sixth century.The Pulpit