Let us say at once, that it appears to us absolutely chimerical to pretend to distinguish, with any degree of certainty, the primitive elements of our Gospels from those subsequently added. The most eminent critics, if guided only by their individual appreciation of texts, and unbiassed by any tradition, come to the most various conclusions upon the same passages. One sees in Matthew evident marks of its being the later composition, while another makes the same observation on Mark. They are not less divided when the question is, whether such and such a narrative presents the tokens of originality or not. The conclusion then must be, that criticism has no certain test for distinctions so delicate; and we are convinced that such a test it never will possess, and that on this path of critical inquiry the arbitrary reigns unchecked.
Edmond de Pressense, Jesus Christ: His Times, Life, and Work, 2nd ed. (London: Hodder and Stoughton, 1868), p. 131