Body and Soul in Ancient Philosophy

Heraclitus on measure and the explicit emergence of rationality 97
"pk÷r teja·letq¸ar, aT dµ let± moO te ja· dºngr aqh/r kocisl` %comtai, 1m
ak¸coir te 1pite¼n, ja· to?r b´ktista l³m vOsim, b´ktista d³ paideuhe?sim.
Moderate or balanced emotions are the outcomes of reason’s rule, or, to
be more precise, the rule of calculation. We may translate logismos by
reason or rationality, but, in doing so, we shall miss Plato’s own insights
if we overlook the mathematical connotations of the word. Logismos is
the disposition or faculty in virtue of which a soul has the capacity to
rule itself – that is to say, impose order and balance on its emotions
and desires through subjecting them to appropriate calculation or measurement
or proportion.
The same cluster of ideas recurs like a Leitmotif throughout the Republic.
Truth, Socrates proposes, is akin to proportion (emmetria, 6,
486d7). Therefore, he infers, persons who are naturally suited to grasp
the truths of reality (i.e. potential philosophers) require an emmetros
mentality. In the dialogue’s final book Socrates offers measuring, counting
and weighing as the activities that correct optical and other illusions
generated by the senses (10, 602d). These, he says, are the function of
the soul’s calculative (logistikon) part, which is its best part precisely because
it puts its trust in measure and calculation.
The message of these passages can, of course, be amplified by reference
to other parts of the Platonic corpus. In the Protagoras (356d-357d)
Socrates proposes that it is the “measuring craft” (metrÞtikÞ technÞ) which
will prevent people from making mistakes in determining what is good
for themselves, where goodness is construed as achieving a preponderance
of pleasure over pain. 16 Similarly in the Philebus (55e) all true crafts
require measure and such measuring methods as weighing and counting.
The final Platonic passage I offer as retrospective to Heraclitus comes
from the Laws (4, 715e7 –716b5), where the Athenian Stranger, imagining
himself addressing the colonists of the newly founded community,
preaches to them as follows:
God, so the ancient account tells us, holds the beginning, the end, and the
middle of all beings and proceeds without deviation in his natural revolution.
He is always accompanied by justice, who punishes those who forsake
the divine law. One who intends to flourish sticks to justice and is compliant
and well ordered, but the person puffed up by arrogance … who thinks
he needs no ruler or guide … is abandoned by God … and utterly ruins
himself, his household and his city.
16 Note also Prt. 326b on the educational need for eqquhl¸a and eqaqlost¸a, and
Phlb. throughout, especially 25e, 26a, and 65a.