Most of these systems come into the category of occult pursuits, as they are the interpretations of phenomena on the ground of fanciful presumptions, by an appeal to unreal or at least unverifiable influences and relations.
It is not, indeed, demonstrable, but there are many presumptions, besides some fragments of direct evidence, which make it more than probable that the old administrative arrangements both of the provinces and of the towns, but especially of the latter, remained practically undisturbed at the period of the Gothic occupation of Spain.'
The doctrine of survivorship originated in the Roman Law, which had recourse to certain artificial presumptions, where the particular circumstances connected with deaths were unknown.
But his plans were traversed again and again by unforeseen complications, the failure of the most promising presumptions, the perpetual shifting of apparently stable alliances; and again and again he had to modify his means to attain his ends.
Of these, including as they do all inductive science, he reports that demonstrable knowledge " is very short, if indeed we have any at all "; and are not thrown wholly on presumptions of probability, or else left in ignorance.