From Blood to Flesh: Homonymy,
Unity, and Ways of Being in Aristotle
Christopher Frey
My topic is the fundamental Aristotelian division between the animate and the
inanimate. In particular, I discuss the transformation that occurs when an inani-
mate body comes to be ensouled. The role Aristotle attributes to blood (αἷμα) in
the nutritive and reproductive processes that effect this transition is well-known.
Blood is the sole matter from which all of our animate tissues are generated and
nourished.
1
But this nutritive role does not exhaust blood’s significance. We can
appreciate this additional import by reflecting upon blood’s unusual status.
Blood, I shall argue, occupies a middle ground between two otherwise mutually
exclusive domains—it is unique in being, at one and the same time, both animate
and inanimate. This is not a trivial claim. For once we understand what it is for
blood to occupy this position, we will possess the resources to explain what it is
for a soul to inform a body. That is, we will be able to explain what it is for the
soul to be both a living organism’s cause of being (αἴτιόν τοῦ εἴναι) and the
principle (ἀρχή) of its bodily unity.
Aristotle’s account of digestion ensures that blood is, at least in part, inani-
mate. Digestion is a multi-stage process of mechanical division and heat-induced
concoction that involves the exercise of active capacities for movement located
in numerous organs and tissues. According to Aristotle, the blood that this pro-
cess yields is not a proper part of an animal; it is simply an advanced phase or
form of nutriment (ἡ τελευταὶν τροφή). As the food we eat stands to the mouth
that chews it or to the stomach that partially digests it, so blood stands to the ves-
sels in which it resides—as an inanimate, foreign body.
2
1
In nutrition, blood is transformed into flesh (σάρξ) through the exercises of capacities for
movement located in an organism’s preëxisting tissues. These movements alter nearby blood in such
a way that it becomes materially indistinguishable from the flesh acting upon it and is thereby assim-
ilated (GC i 5.322a5-16; JSVM 3.468b31-469a9; PA ii 3.650a1-36, iii 5.668a4-20; GA i 19.726b5-6,
and ii 6.743a3-21). The same sort of movements occur in generation with one important difference:
the capacities are not located in an organism’s preëxisting flesh but belong to the progenitor’s semen
and are exercised upon a female’s blood-like, reproductive residue (καταμήνια, GA i 19.727a1-4,
b31-33). καταμήνια is the matter from which all animate tissues come to be in generation. Here and
throughout, I drop the standard rider ‘or the analogous part in bloodless animals’ and will tend to
focus on flesh alone from among the multitude of an organism’s living tissues.
2
Blood is occasionally found on lists of the parts of animals (PA i 1.640b18-20, ii 2.647b10-16,
and HA iii 2.511b1-10). But there are many reasons to take Aristotle’s considered view to be that
blood is not among an organism’s proper parts. Ε.g., Aristotle (i) takes the insensitivity of blood to
count against its being a part (HA iii 19.520b14-16; PA ii 3.650b4-6, 5.651b4-7, and 7.652b4-7), (ii)
often speaks of blood-filled organs and blood vessels as being mere containers (PA ii 1.647b2-3,
3.650a32-36, 650b6-7, iii 4.666a16-19, 5. 668a14-b1, 667b19-21; GA ii 6.743a10-11, and
Spir. 5.483b19ff.), (iii) includes other residues on these lists, e.g., bile (PA ii 2.647b13), that he
Ancient Philosophy 35 (2015)
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