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are equally related to the physical environment. These lan- guages also require special training for understanding them, yet these differences, as much morphological as intellectual, are of simple particularities which do not destroy the general anatomical structure nor the fundamental structure, common and universal in intelligence. Also, the laws of the formation and evolution of languages seem necessarily uniform, despite their variations and limited oscillations. What is harmony from the point of view of the musical scale for the auditory nerves of certain races is not for others. But these differences are not absolute; there are laws of the harmony of sounds, then of natural limits, statics, in a word, of all the particular dissonances.
The main point is that the cercle de la conscience, as Ribot says, the Umfang des Bewusstseins, as the Germans say, remains always a limited circle. Limitation is a constant and necessary condition, a law of thought.
Let us consider magnitudes. I think of a measure, say a meter or centimeter. As I have each idea in turn somewhat well defined, I thereby have a somewhat definite idea of their relation. On the other hand, our capacity to think relations becomes partly ineffective when one of the terms is undefined. In that case the relation eludes representation. This is the basis of the theory of the unknowable a theory, moreover, as I have elsewhere pointed out, which is false in the absolute sense. In a word, even in this case the relation, which is nothing but a quasi-empty form, still retains a certain quality. If the quantitative measure is not possible, there remains a general qualitative appreciation, vague in its character, of exten- sion, of duration, and of force. But if even this purely qualitative representation of one of the terms of the relationship can no longer be presented to consciousness, there is no longer a rela- tionship, and consequently no knowledge; that is, we can appre- ciate phenomena in correlation with each other and not otherwise. The law of thought is that it is not able to pass the frontiers of the relative.
"When we try," says Herbert Spencer, 1 "to go beyond the
1 Essays Scientific, Political, and Speculative.
