106. Time Reckoning
Still another case of primary parallelism is provided by the Maya-Aztec system of time denotation by coupling two series of symbols in an overlapping system of permutations, as described below (§ [197]). This is as if we denoted the successive days of the year 1 January, 2 February, 3 March, and so on, until, having come to 12 December we went on 13 January, 14 February, and so once more around until 31 July was reached, when the next days would be 1 August and 2 September instead of February 1 and 2. Cumbersome and strange as this system appears, an exact parallel to it in principle was devised by the Hellenistic philosophers when they coupled the twenty-four hours of the day with the seven planets in a 168-hour cycle which gave the order and names to the days of the week (§ [124]). A third case occurs in China where ten “celestial stems” and twelve “terrestrial branches” were permutated to form a sixty year chronological cycle.[16] All three of these devices are based on the same mathematical principle and serve the same end of time reckoning. But their content and result is different. The Greeks combined 24 with 7, the Chinese 12 with 10, the Mayas 13 with 20 and 260 with 365; and the periods treated ranged from hours to years.
These cases of primary parallelism allow the inference that there are certain inherent tendencies of the human mind in certain directions, such as operation in rebus reading, syllabic writing, reckoning by least common multiples. Here, then, is a seeming approach for a definite psychological interpretation of the history of civilization. Yet the results of such a method of attack must not be overestimated. The generic manner of culture in these several instances is indeed uniform enough to permit the conclusion that it springs from a uniform impulse or bent of the mind. But all the particular, concrete content of these cultural manifestations is as diverse as their historical origins are separate; which means that psychology may explain what is psychological in the cases, but that a larger cultural constituent remains over before which the generically valid principles of psychology are ineffective as explanations. As in the case of the influence of physical environment it might be said that psychological factors provide the limiting conditions of cultural phenomena.