When the main argument rests upon some single fact of primary weight or importance, a single fact to which nothing of equal magnitude can be opposed, the neglect of subordinate details is excusable--at least, in a short work. If they come spontaneously, and are of a satisfactory character--well and good. They are no part of the leading argument.
In some cases, perhaps, it should be a matter of principle to abstain from them; for example, when the leading argument, although good in itself, is liable, either from its novelty or from the amount of previous opinions which it contradicts, to be undervalued. In such a case, the display of subsidiary minutiæ subtracts from its weight. They make it look weaker than it is; weak enough to require all the support that the skill of its author can devise. In deducing the Greeks from Italy, the relations between the Greek and Latin tongues, the great difficulty of explaining them otherwise than by a geographical continuity, and the equal difficulty of effecting this continuity by any of the ordinary means formed the palmary argument. Such details as fell in with this view were put down to gain (_apposita lucro_). They were also good against similar details on the opposite side. But they were _ex abundanti_--at least in the first instance. To have neglected them altogether would not have been too bold. To have paraded them unnecessarily would have subtracted from the value of the real argument.
A comparative depreciation of subsidiary details appears in the present question; wherein it is held that certain members of the Lithuanian family extended their area across the Baltic into parts of Scandinavia, and peopled the southern provinces of Sweden. These were the Goths of Gothland, the Jutes of Jutland, the Vites of Withesleth, the old name of the Danish islands, anterior to their occupation by the Danes. The critic who doubts whether the names are the same as that of the Goths, on the strength of the difference of form, is free to do so; but by doing so, he will only impugn a part of the present doctrine. That the Goths of Gothland are the Gothones, Guttones, or Gythini of the opposite coast of Prussia and Courland is the important inference; and that the appearance of identical or similar names on the opposite coasts of an inland sea of no considerable breadth is a phenomenon which, until it can be explained otherwise, must be presumed to denote ethnological affinity is the principle which supports it. Whether the Gothones of Courland were really and truly Lithuanian is a point upon which there may be a difference of opinion; but there should be no difference of opinion as to the explanation of the presence of Goths in the opposite country of Gothland. The common-sense view of the matter, and the ordinary habits of interpretation should take their course.