There is not much doubt that the third and fourth of these tribes are the same, and it is quite likely that the Magyars are descended from the horde which sent forth the Huns in the 4th century, but it is not demonstrable.
All around the coast the diminution in the numbers of the remaining species of terns is no less deplorable than demonstrable.
Above all, he broke with the prevalent view which regarded theology as essentially intellectual in its appeal and demonstrable by processes of exact logical deduction.
In one form or another such a theory of human descent has in our time become part of an accepted framework of zoology, if not as a demonstrable truth, at any rate as a working hypothesis which has no effective rival.
It is thus demonstrable that the material for our Grail legend, in its present form, existed long anterior to any extant text, and there is no improbability in holding that a confused tradition of pagan mysteries which had assumed the form of a popular folk-tale, became finally Christianized by combination with an equally popular ecclesiastical legend, the point of contact being the vessel of the common ritual feast.