There is one more point to be noted; namely, the idea that the differentiation of languages takes place in relatively recent time. The idea of time is naturally connected with the general advance of knowledge as to human history. First, the linguist had to place the process of evolution within a short period from the Tower of Babel to his own days. Later, the period was extended over a longer period, but still covering a very short period, and the linguist practically never attempted to extend it past historical times. The sight of linguists of the eighteenth century and of the beginning of the last century was limited by a period of a few thousand years. In the meantime, successful archaeological investigations have shown that mankind is at least several tens of thousands of years old. This fact has been usually omitted, for the chance of observing primitive languages has been greatly reduced. Yet the question was put and sometimes answered in the sense that man of the quaternary geological period did not speak at all. This was a hypothesis good only for soothing the mind and thus it discards the inconvenient facts of a possible great age of human speech. Further discoveries along the same line, of which the essential one is a further increase of man's age, — this time to hundreds of thousands of years, — were left unnoticed, better to say, ignored. The avenue of escape was again found in the suggestion that only the species Homo sapiens must be considered in the problem of language. However, anthropologists, such as M. Boule, have recognized that the man of the old Paleolithic might have speech, and since it has already been suggested, for example, by E. Smith, that the human ancestors. such as the Pithecanthropus erectus, and other species of man might have a certain ability of speech, the problem of the «origin» of languages ought to be brought perhaps to the tertiary period and even to other animals, for these predecessors of Homo sapiens without having been «human» at all, were not, perhaps, speechless. Such a historic remoteness for the origin of language and such hoplessness in finding reliable documents as to «primitive» language were sufficient to discourage the linguists in finding scientific documentation of their theories, so the facts regarding the physical history of man have lost their interest in the eyes of linguists. On the other hand, owing to the shortness of the periods of seizable documents, the period left for «evolution» was thus limited and not by the lack of other documents, but by the lack of historic persepective [62]. In this respect, as in the case of the theory of evolution, most linguists have limited themselves by omitting facts of greatest importance for their own studies.
62. Cases like that of P. Rivet, who has a very broad view as to the historic remoteness of some linguistical and ethnical groups, are rather exceptional.