Supposing it to be shown that some of the allusions which are thought to be taken from our Gospels were merely accidental coincidences of language, this would not materially affect the part of the evidence which could not be so explained.

Supposing even that some of these allusions could be definitely referred to an apocryphal source, the possibility would be somewhat, but not so very much, increased that other instances which bear resemblance to our Gospels were also in their origin apocryphal.

But on the other hand, if a single instance of the use of a canonical Gospel really holds good, it is proof of the existence of that Gospel, and every new instance renders the conclusion more probable, and makes it more and more difficult to account for the phenomena in any other way.
The author of 'Supernatural Religion' seems to have overlooked this.

He does not seem to have considered the mutual support which the different instances taken together lend to each other.

He summons them up one by one, and if any sort of possibility can be shown of accounting for them in any other way than by the use of our Gospels he dismisses them altogether.