the world in motion'. But there is little evidence of any interdisciplinary influence or understanding.
Problems of perception engaged the philosophers, and observational difficulties troubled the astronomers:
the two areas did not overlap. The scientists discussed questions of method, and the philosophers
speculated on the foundations of knowledge: the two enquiries were separately conducted. Astrology has
been thought to link science and philosophy inasmuch as the astronomers may have regarded their science
as a servant of astrology while the Stoics' fatalism made them likely to succumb to that occult science.
But the link is tenuous. Hipparchus is said 'to have shown that we are related to the stars and that our
souls are a part of the heavens', but that report is vague, and it is unlikely that the Hellenistic astronomers
anticipated Ptolemy's addiction to astrology. Moreover, there is little evidence for any interest in astrology
on the part of the Old Stoa.
In truth, the philosophers did not care for mathematical arcana, and the mathematical scientists ignored
philosophy - they were more interested in the technological applications of their studies than in any
theoretical speculations. Thus engineers such as Ctesibius of Alexandria (fl. c. 270), Philo of Byzantium
(fl.c.200), Hero of Alexandria (fl.c.6o), and Archimedes amused themselves and diverted their masters by
inventing new machinery - water-clocks and mechanical puppets, fire-pumps and steam-toys, and many
engines of "war.
Hellenistic astronomy was rivalled only by Hellenistic medicine, the protagonists of which were
Herophilus of Chalcedon (fl. c. 270) and Erasistratus of Ceos (fl.c.260). Both men were practical
physicians. Herophilus had an interest in new drugs, and he also developed a diagnostic technique which
relied upon distinguishing different types of pulse. Both men were also interested in the theoretical
aspects of medicine. Herophilus was the first scientist to describe the structure and function of the
duodenum, an organ which is still known by the name Herophilus gave it. He also examined the brain.
Erasistratus developed a physiological theory which rested on mechanical principles. The theories had an
empirical base:
Herophilus and Erasistratus ... were given criminals from the prison by the kings < of Egypt > and
dissected them alive: while they were still breathing they observed parts which nature had formerly
concealed, and examined their position, colour, shape, size, arrangement, hardness, softness, smoothness,
connection ...
Nor is it cruel, as most people allege, by causing pain to guilty men - and only a few at that - to seek out
remedies for innocent people of every age.