Is it likely that he would have cut down a document previously existing?
or, have we reason for thinking that he would be scrupulous in keeping such a document intact?
The author of 'Supernatural Religion' himself makes use of this very argument; but I cannot help suspecting that his application of it has slipped in through an oversight or misapprehension.

When first I came across the argument as employed by him, I was struck by it at once as important if only it was sound.

But, upon examination, not only does it vanish into thin air as an argument in support of the thesis he is maintaining, but there remains in its place a positive argument that tells directly and strongly against that thesis.

A passage is quoted from Canon Westcott, in which it is stated that while Tertullian and Epiphanius accuse Marcion of altering the text of the books which he received, so far as his treatment of the Epistles is concerned this is not borne out by the facts, out of seven readings noticed by Epiphanius two only being unsupported by other authority.

It is argued from this that Marcion 'equally preserved without alteration the text which he found in his manuscript of the Gospel.' 'We have no reason to believe the accusation of the Fathers in regard to the Gospel--which we cannot fully test-- better founded than that in regard to the Epistles, which we can test, and find unfounded' [Endnote 217:1].