Body and Soul in Ancient Philosophy

Galen and the Stoics: What each could learn from the other 411
adopted Galen’s ideas. 7 For the Stoics, the main gain would have been
methodological. The quality of Galen’s argumentation for locating the
ruling part of the psyche, understood as the seat of sensation and motivation,
in the brain rather than the heart is, I think, by any standards, far
better than the Stoic case for locating it in the heart. Galen’s arguments
reflect the methodology that lies at the heart of his medical technique
and natural investigation. This is a considered combination of logical argument
and empirical observation, supported by a sophisticated account
of causation. 8 Galen’s investigation of the relative functions of heart and
brain, established by ligature (cutting access to nerves and blood-vessels,
respectively) is generally reckoned to be highly comparable with modern
experimental method, and to be one of the major achievements of
ancient science. 9 In logical form, Galen’s argument centres on identifying
an appropriate middle term, which determines whether the organ in
question has (as a unique or distinctive attribute) the characteristic relevant
for acting as the base for the functions of the ruling part. Galen
assumes that the relevant middle term and distinctive attribute is that
of being the beginning or source (archÞ) of the nerves. He offers proof
of the claim that only the brain meets this criterion by a set of empirically
based observations conducted by vivisection of animals. In particular,
Galen demonstrates that cutting the laryngeal nerves, which start in
the brain, paralyses the function of speech, whereas cutting the windpipe
beneath the larynx (with connections to the heart still intact)
does not have this effect. 10
On the Stoic side, their arguments for locating the ruling part or
control-centre in the heart are not of comparable cogency, at least as
far as the question of location is concerned. These arguments are better
7 Stoicism remained an influential and in some sense a living philosophical movement
until at least Galen’s time (A.D. 129 – ca. 210); on Galen’s relationship
with contemporary Stoics, see Tieleman forthcoming. But my concern here
is with Stoicism in its original, Hellenistic form.
8 On this method, see Frede 1987, 279 –298, Barnes 1991, Hankinson 2003 and
forthcoming.
9 See Debru 1994, Tieleman 2002, Rocca 2003.
10 See Tieleman 2002, 260–268, referring especially to PHP V.228, 2.4.5 – 6,
V.232 – 7, 2.4.25 – 39, V.655, 8.1.22 – 4. (References to PHP cite the volume
and pages numbers in the standard Kühn edition of Galen’s works, followed
by the books, chapters and sections, and in some cases page and line numbers
in the edition of PHP by De Lacy 2005. References to other Galenic works
cite the Kühn pages where relevant, together with chapters and sections in
modern editions.) See also Hankinson 1991, 218 – 229, Tieleman 1996, ch. 3.