Finley is addressing the work of Maurice Goguel (best known among some of us here for his book against the mythicism of his day) and comes to something by another well-known name, A.N. Sherwin-White:
So we see that Finley called out the rhetorical sleights of hand practised by Jesus scholars.An Oxford historian, Mr A. N. Sherwin-White, has recently insisted that the life of Christ as told in the Gospels and the life of Tiberius as related by Tacitus or the account of the Persian Wars in Herodotus are all of a kind, subject to the same tests and having the same general aims. ‘Not’, he adds, ‘that one imagines that the authors of the Gospels set to work precisely like either Herodotus or Thucydides.’ Not precisely? Not at all. He has forgotten that the Greek verb at the root of ‘history’ is historein, to inquire, which is what Herodotus set out to do, and what the authors of the Gospels (or the apologetic writers and theologians) did not set out to do. The latter bore witness, an activity of an altogether different order.
Finley then turned to a work exploring the nature of history:
"With no external controls"? That is the very phrase I have been using in my own criticisms of the methodology used by biblical scholars presenting themselves as historians. It is nice to see I have some support from a renowned deceased scholar.In R. G. Collingwood’s justly famous dictum,
The real difficulty begins if one agrees with Collingwood. Once the existence of a process of myth-making is accepted, the question is, How does one make a history out of such historiographically unpromising materials? There are no others. A handful of sentences in pagan writers, wholly unilluminating, and a few passages in Josephus and the Talmud, tendentious when they are not forgeries, are all we have from non-Christian sources for the first century or century and a half of Christianity. It is no exaggeration to say that they contribute nothing. One must work one’s way as best one can with the Christian writings, with no external controls.theocratic history ... means not history proper ... but a statement of known facts for the information of persons to whom they are not known, but who, as worshippers of the god in question, ought to know the deeds whereby he has made himself manifest
But back to Goguel. This was before the days of formalized (ossified) concepts of "criteria of authenticity" but we can see where the precursors fit when he speaks of "logical and psychological" tests (= criteria of coherence, plausibility...):
The emphases are my own, of course.One simple example will suffice. When asked by the Pharisees for ‘a sign from Heaven’, Jesus replied, ‘There shall be no sign given unto this generation’ (Mark viii, 11-12). Goguel comments:
It follows that stories like those of Jesus walking on water are ‘extremely doubtful’. His healing, on the other hand, may be accepted, and, in conformity with the beliefs prevailing at the time, ‘it is true that these healings were regarded as miracles both by Jesus himself and by those who were the recipients of his bounty.’This saying is certainly authentic, for it could not have been created by primitive Christianity which attached a great importance to the miracles of Jesus ... This leads us to think that Jesus did not want to work marvels, that is to say, acts of pure display.
This application of the ‘psychological method’ is neat, plausible, commonsensical. But is the answer right? Not only in this one example but in the thousands upon thousands of details in the story upon which Goguel or any other historian must make up his mind? I do not know what decisive tests of verifiability could possibly be applied. The myth-making process has a kind of logic of its own, but it is not the logic of Aristotle or of Bertrand Russell. Therefore it does not follow that it always avoids inconsistency: it is capable of retaining, and even inventing, sayings and events which, in what we call strict logic, undermine its most cherished beliefs. The difficulties are of course most acute at the beginning, with the life of Jesus. One influential modern school, which goes under the name of ‘form-criticism’, has even abandoned history at this stage completely. ‘In my opinion,’ wrote Rudolph Bultmann, ‘we can sum up what can be known of the life and personality of Jesus as simply nothing.’
It does not appear that Finley was prepared to go along with the methods, let alone conclusions, of biblical scholars in their efforts to establish what was historical about Jesus.
I doubt that he was a shag on a rock.
Yes, Finley's meaning was clear: without controls no historical reconstruction of any kind can be made from the gospel sources.