1 The Birth of Science - MSRI

250 10. Lost Science
dialogue; 72 his name is even mentioned explicitly (though in the context
of optics). All this makes it very probably that the “weirdnesses” ridiculed
by Lamprias come from Hipparchus’ work, possibly through intermediates.
72a
10.4 Ptolemy and Hellenistic Astronomy
One often hears that the Almagest rendered earlier astronomical works
obsolete. 73 This view is inconsistent with a crucial, if often overlooked,
reality: whereas astronomy enjoyed an uninterrupted tradition down to
Hipparchus (and especially in the period since Eudoxus), the subsequent
period lasting almost until Ptolemy’s generation witnessed no scientific
activity: there was a deep cultural discontinuity. This break, attested in
different ways, is illustrated especially clearly by the astronomical observations
mentioned in the Almagest. They are spread over a period of nine
centuries, from 720 B.C. to 150 A.D., but leaving a major gap of 218 years:
from 126 B.C., the date of the last observation attributed to Hipparchus, to
92 A.D., corresponding to a lunar observation by Agrippa (see Figure ??).
It was during this hiatus that intellectual conquests such as the possibility
of consciously creating new terms or new pictorial styles were aban- page 312
doned, together with the ability to formulate new sets of postulates. We
have already seen in several cases how the interruption of oral transmission
made ancient works incomprehensible. (As a further example among
many possible, consider that Epictetus, regarded at the beginning of the
second century A.D. as the greatest luminary of Stoicism, freely confesses
to being unable to understand the works of Chrysippus: 75 a fact that helps
explain their disappearance.)
The loss of the scientific method led to a “realistic” interpretation of
surviving scientific theses: they were no longer regarded as statements
within a model but as absolute statements about nature. In astronomy,
decompositions of planetary motions, which had been invented in the
early Hellenistic period as mathematical models useful in calculations,
were now in the imperial period regarded literally, each component motion
having its physical reality. Even the concentric spheres of Eudoxus
72
See notes 61 and 62 immediately above.
72a
Further evidence for a Hipparchan planetary dynamics comes from Roman sources; see Section
10.6.
73
[Ptolemy/Toomer], p. 1: “. . . its success contributed to the loss of most of the work of Ptolemy’s
scientific predecessors, notably Hipparchus, by the end of antiquity, because, being obsolete, they
ceased to be copied.” Likewise [Grasshoff], p. 1.
75
Epictetus, Enchiridion, xlix.
Revision: 1.11 Date: 2003/01/06 02:20:46