"Not only the tools of manual labour, but also the tools of human thought — words — are subject to the laws of historical development. The history of the meanings of words is outside the area of interest of formal logic, and could not be fruitfully studied by the methods of that discipline. The history of language in what is its most essential content is the history of language as a social instrument of thought; it is historical epistemology which cannot be studied within the scope of any other discipline. The linguist is of necessity only marginally interested in all conventional terminology, whereas certain votaries of formal logic are inclined to investigate domains which are alien to linguistics and even to some extent in contradiction to its basic assumptions!"