d formerly thought. Sogdian merchants who later played a great role in
commercial contacts might have been active already from 350 or 400 B.C.
on and might have been the transmitters of new ideas. The most important
philosopher of this school was Tsou Yen (flourished between 320 and 295
B.C.); he, as so many other Chinese philosophers of this time, was a
native of Shantung, and the ports of the Shantung coast may well have
been ports of entrance of new ideas from Western Asia as were the roads
through the Turkestan basin into Western China. Tsou Yen's basic ideas
had their root in earlier Chinese speculations: the doctrine that all
that exists is to be explained by the positive, creative, or the
negative, passive action (Yang and Yin) of the five elements, wood,
fire, earth, metal, and water (Wu hsing). But Tsou Yen also considered
the form of the world, and was the first to put forward the theory that
the world consists not of a single continent with China in the middle of
it, but of nine continents. The names of these continents sound like
Indian names, and his idea of a central world-mountain may well have
come from India. The "scholars" of his time were quite unable to
appreciate this beginning of science, which actually led to the
contention of this school, in the first century B.C., that the earth was
of spherical shape. Tsou Yen himself was ridiculed as a dreamer; but
very soon, when the idea of the reciprocal destruction of the elements
was applied, perhaps by Tsou Yen himself, to politics, namely when, in
connection with the astronomical calculations much cultivated by this
school and through the identification of dynasties with the five
elements, the attempt was made to explain and to calculate the duration
and the supersession of dynasties, strong pressure began to be brought
to bear against this school. For hundreds of years its books were
distributed and read only in secret, and many of its members were
executed as revolutionaries. Thus, this school, instead of becoming the
nucleus of a school of natural science, was driven underground. The
secret societies which started to arise clearly from the first century
B.C. on, but which may have been in existence earlier, adopted the
politico-scientific ideas of Tsou Yen's school. Such secret societies
have existed in China down to the present time. They all contained a
strong religious, but heterodox element which can often be traced back
to influences from a foreig