Such structures anchor the development of philosophy in all historical
regions. If we turn to ancient Greece, we find the history of philosophy can be
recounted in terms of a series of interlinked groups: the Pythagorean brother-
hood and its offshoots; Socrates’ circle, which spawned so many others; the
acute debaters of the Megara school; Plato’s friends, who constituted the
Academy; the breakaway faction that became Aristotle’s Peripatetic school; the
restructuring of the network that crystallized with Epicurus and his friends
(very tight bonds here), withdrawing into their Garden community, and their
rivals, the Athenian Stoics, with their revisionist circles at Rhodes and Rome;
the successive movements at Alexandria.
Many parallels can be cited in China. I will mention just one: the Neo-Con-
fucians of the Sung dynasty, the most important development of Chinese
philosophy since the early Warring States. Like the German Idealists, the
Neo-Confucians burst on the scene in two overlapping generations, in this case
active around 1040 to 1100 via a group linked by personal ties. Those who
became notable were the brothers Ch’eng Hao and Ch’eng I; their teacher
Chou Tun-yi; their father’s cousin Chang Tsai; and their neighbor Shao Yung.
There were tensions and differences among the group, and various lines of
disciples split off from them. Once again we see the organizing core: the Ch’eng
brothers were instrumental in linking the others together, and it was through
their movement that the earliest thinker, Chou Tun-yi, retrospectively acquired
his reputation as a founder. (This relabeling parallels, in a degree, the experi-
ence of Kant.) The subsequent politics of the movement, as it split into rival
factions and received its canonical formulation in the fourth generation by Chu
Hsi and Lu Chiu-yüan, exemplify structured processes that are historically
general.
In Europe such groups have structured the main intellectual movements
from the 1600s to the present. The correspondence network formed by Marin
Mersenne in Paris in the 1620s, and extended to England by Henry Oldenburg,
was the organizing basis of what eventually became the French Académie
des Sciences and the English Royal Academy in the 1660s. In a larger sense,
the “invisible college” continued for more than 60 years, providing an organ-
izational core for the founding generations of modern Western philosophy.
Growth in the sheer size of the surrounding population or expansion in the
total numbers of educated intellectuals does not outdate these concentrated
groups who dominate attention at the innovative core. In our own times we
find again two close-knit groups with major intellectual impact: the Vienna
Circle of the 1920s and 1930s, whose subsequently scattered followers (and
visitors, such as Ayer and Quine) dominated Anglophone philosophy through
midcentury; and the Paris existentialists of the 1930s and 1940s, whose after-
math includes most of the famous names of the 1960s and 1970s.
Another pattern of creativity is intergenerational networks, chains of emi-
Introduction^ •^5