Open Journal of Philosophy
2013. Vol.3, No.1, 47-54
Published Online February 2013 in SciRes (http://www.scirp.org/journal/ojpp) http://dx.doi.org/10.4236/ojpp.2013.31008
Copyright © 2013 SciRes. 47
Does Aristotle Refute the Harmonia Theory
of the Soul?
Douglas J. Young
Department of Philosophy, Lycoming College, USA
Email: young@lycoming. edu
Received October 24th, 2012; revised November 27th, 2012; accepted December 10th, 2012
In Aristotle’s On the Soul he considers and refutes two versions of the harmonia theory of the soul’s rela-
tion to the body. According to the harmonia theory, the soul is to the body what the tuning of a musical
instrument is to its material parts. Though he believes himself to have entirely dismissed the view, he has
not. I argue that Aristotle’s hylomorphic account is, in fact, an instance of the harmonia theory.
Keywords: Aristotle; Soul; Body; Hylomorphism; Harmonia; Tuning; Mind-Body Problem
Aristotle begins On the Soul by surveying his predecessors’
views (1.2 - 5). He describes one, the harmonia theory, as both
popular and persuasive (Ross, 1961: 1.4.407b27-30). According
to this view, the soul “is a kind of tuning (harmonia)” of the
body’s constituent parts (407b30). A lyre’s tuning, for example,
is the precise arrangement of its wood, pegs, and strings in
virtue of which it can be played in a particular mode. According
to the harmonia theory, the soul is the “tuning” of the body’s
constituent parts in virtue of which it is alive. Aristotle goes to
great lengths to refute the harmonia view, despite the apparent
similarity to his own hylomorphic account of the soul and body.
This has long puzzled commentators. It seems that successful
arguments against the harmonia view undercut Aristotle’s ac-
count of the soul as the form of a living body.
In this paper I argue that Aristotle can coherently reject the
harmonia theory without undermining his own view. My case
turns on recognizing that there are different specifications of the
harmonia account. Aristotle considers, and rejects, only two.
According to the first, the soul is a “blending or combining of
opposites” (407b30-31). According to the second, the soul is
the “ratio or combination” of the parts of the body (407b32-33).
Aristotle takes these two arguments as decisive against the view,
but they aren’t. Even if both arguments were sound, he would
not have disentangled himself from the harmonia view. Over-
looked in this debate, I claim, is that a harmonia can be a com-
posite material object. I argue that Aristotle is committed to the
view that the functionally organized, living body is itself a ma-
I’m not alone in noting the similarity between the harmonia
view and Aristotle’s positive account. In fact, there is a re-
markable unity of opinion among Aristotle’s commentators,
both ancient and modern. Themistius, in his fourth century
commentary on On the Soul, says that those arguing that the
soul is a harmonia are “none too close, nor yet too far, from the
truth” (Todd, 1996: 25.23-24; Heinze, 1899). These sentiments
are echoed by modern commentators as well. R. D. Hicks re-
ports that the harmonia theory is “the one which approaches
most nearly to his own formula that the soul is a form... of a
natural body capable of life” (Hicks, 1907: p. 263; Ross, 1961:
p. 195). Jonathan Barnes agrees and goes even further. The best
sense he can make of Aristotle’s claim that the soul is an “en-
telecheia (i.e., actuality) of a potentially living body” is to read
it as a version of the harmonia theory (Barnes, 1982: pp. 491-
492; Charlton, 1985: p. 131). Though commentators have re-
cognized this similarity, they resisted a materialist understand-
ing of the harmonia view.
Aristotle considers the harmonia view, in part, because it
seems to avoid a mistake he finds in Plato and the Pythagoreans.
Dualist accounts of the Platonic and Pythagorean sort fail to
adequately explain why one soul is “attached” to one body.
According to Pythagoras it is possible, Aristotle complains,
“for any old soul to be inserted into any old body” (407b21-23).
Aristotle thinks such metempsychosis is as absurd as the trans-
migration of carpentry into flutes. The harmonia view avoids
any such absurdity; one soul is ontologically dependent on one
body’s constituent parts just as an individual lyre’s tuning is
dependent on its wood, pegs, and strings. Aristotle’s stated aim
in the opening of On the Soul is to adopt what his predecessors
got right and to avoid what they got wrong (1.2.403b23-25). As
it turns out, the harmonia theorist gets quite a lot right and per-
haps, more than Aristotle realized.
Understanding the Alternatives
After noting the provenance and the popularity of the har-
monia theory, he explains how it is commonly understood:
“People say that the soul is some sort of harmonia; for, they say ,
a harmo nia i s a blending and combination (krasi n kai sunthesin)
of contraries, and the body results from a combination of con-
traries” (1.4.407b30-32). Aristotle clarifies the popular version,
suggesting that a harmonia should be understood in one of two
ways. A harmonia is either:
1) A ratio of the things mixed (logos... tôn mixthentôn,
2) A composite (sunthesis, 407b33).
His strategy for defeating the harmonia theorist appears to be
a simple dilemma. A harmonia is either a ratio of the things
mixed or a composite. He argues that on either specification,
the soul cannot be a harmonia. But because it’s not obvious
how Aristotle means us to understand these two alternatives, a
D. J. YOUNG
bit more detail is in order.
The First Alternative: A Ratio of the Things Mixed
According to the first alternative, a harmonia is a ratio of the
things mixed. In order to unpack this claim, we need to take a
closer look at what he has to say about mixtures. Aristotle’s
fullest treatment of that topic is found in On Generation and
Corruption 1.10 (Joachim, 1970).
There Aristotle imagines a skeptic who argues that mixture is
impossible. Consider a case where two ingredients are com-
bined, wine and water say. The skeptic argues that one of three
things can happen. First, both the ingredients might continue to
exist, unaltered, in the resulting combination. In your glass you
have a layer of wine, topped with a layer of water. The ingre-
dients haven’t been mixed in that case, because there has been
no change (other than spatial) in the ingredients. Second, one or
the other of the ingredients might be destroyed. A drop of wine
in the sea, Aristotle claims, doesn’t result in a very dilute mix-
ture of wine and water. The wine, he claims, is destroyed. It is
converted into water, resulting in a sea that is one drop fuller1.
This is not a case of mixture. Third, both of the ingredients
might be destroyed. Again we have a case of destruction, not
mixture. So since the ingredients of the combination must ei-
ther exist unaltered or are destroyed, the skeptic concludes that
mixture is impossible.
Aristotle doesn’t think that we must, on account of these
skeptical worries, be saddled with their conclusion. Mixture is
possible. So Aristotle invokes these skeptical suggestions for
another purpose—they are meant to highlight the characteristic
features a proper mixture must have. Aristotle claims there are
First, the elements from which the mixtures are formed must
react with one another altering the properties of each (327b1-2;
328b23). The result of this alteration is that the mixture is
something different than a mere juxtaposition of the elements
(Heinaman, 1990: p. 89). Stirring together a spoonful of barley
and a spoonful of wheat won’t leave you with a mixture. The
ingredients which go into a mixture must undergo a change of
Second, the elements exist potentially, but not actually, in the
mixture (327b24-26). The ingredients which jointly compose
the mixture are not destroyed, as the skeptic thought they might
be; they are rather demoted to the level of only existing poten-
tially (Fine, 1996: p. 91). This feature of mixtures is problem-
atic and difficult to understand2. But let the following suffice as
a first approximation of what Aristotle means here. He says that
the constituents exist in the mixture and are not destroyed be-
cause “their power to act is preserved” (dunamis, 327b31).
What gets preserved in the mixture are (some of) the causal
powers of the ingredients. Consider bronze mixed with some
tin. He explains that when the two metals are mixed, the tin
nearly disappears, imparting only its color to the bronze
(328b12-13). The causal power of the tin to appear a certain
color is actually preserved in the alloy, but the tin itself exists
Third, the alteration that takes place between the ingredients
results in something whose smallest parts are all the same and
which all have the same character as the whole (328a5-10),
something homoeomerous (Joachim, 1904: p. 75). “It must be
the case”, Aristotle writes, “that if something is mixed, the mix-
ture is homoeomerous just like any part of water is water”
(328b10-11). The mutual alteration that takes place between the
ingredients results in a mixture that really is something differ-
ent, a tertium quid, in which the original elements exists merely
Finally, all the homoeomerous composites Aristotle consid-
ers are mixtures of all the four elements—earth, air, fire and
water. Again he writes: “All the mixed bodies which exist
around the region of the center (i.e., the Earth) are compounds
of the simples” (2.8.334b32-34). So all homoeomerous com-
pounds have the same constituents. What distinguishes one
from another, blood from bone, for example?3 The ratio or pro-
portion of each element in that compound. Bone has propor-
tionally more earth in it than blood does; blood has proportion-
ally more water in it than bone has. Since each of these mix-
tures are composed of the same four elements, the defining
feature of each homoeomerous compound is the ratio according
to which those ingredients have been mixed.
Aristotle’s first alternative is, I hope, clearer. When he says
that a harmonia is the ratio of things mixed, he means that it’s
the ratio according to which the four elements are combined in
the homoeomerous parts of the body.
The Second Alternative: A Composite
Let us now turn to the second alternative Aristotle presents—
the view that a harmonia is a composite. To unpack what he
has in mind here, we’ll need to look into his physics and his
First for the physics. After his initial presentation of the two
alternatives, he suggests that the word “harmonia” has two ap-
plications: “the most proper pertains to magnitudes which have
motion and position, where it (i.e., the harmonia) is a compos-
ite of them” (On the Soul: 1.4.408a6-8). This alternative seems
to express a materialist thesis—a harmonia is something com-
posed of material parts. To show that this is the case we need to
determine what “magnitudes which have motion and position”
A magnitude is a particular quantity. A magnitude with a po-
sition, then, is a particular quantity located in some place. In
Physics 4.1 - 5 Aristotle investigates what it means for some-
thing to have a place or to be in a place. He explai ns that place
“has three dimensions—length, breadth, and depth—the di-
mensions by which all bodies are bounded” (Ross, 1960:
4.1.209a5-6). Since something that has a place is bounded by
three dimensions and something that has a place has a position,
something that has a position is bounded by three dimensions.
A magnitude which has a position, therefore, is a spatially ex-
tended quantity of stuff.
1In On Generation and Corruption 1.10.328a2-25 he writes that “if a great
quantity (or large bulk) of one of these materials be brought together with a
little (or with a small piece) of another, the effect produced is not mixture
but the increase of the dominant; for the other material is transformed into
the dominant. That is why a drop of wine does not mix with ten-thousand
gallons of water; for its form is dissolved and it is changed so as to merge
with the total volume of water”.
2This feature of Aristotle’s mereology seems to distance it from contempo-
rary acc o un t s .
But such a quantity is also capable of motion. Motion in its
most general and proper sense Aristotle tells us, is a change of
place. In order for something to move, that thing must first be
3Aristotle thinks blood, bone and sinew are examples of such homoeomer-
ous compounds. See, for example, Generation and Corruption: 1.1.314a20;
: 4.12.389b23-29 and Parts of Animals: 1.1.640b20.
Copyright © 2013 SciRes.
D. J. YOUNG
in one place and then in another. Since motion is a change of
place, a fortiori that thing must be located in a place. Only spa-
tially extended objects, then, are capable of motion4. So we can
conclude that a magnitude which has motion and position is a
quantity of stuff that is extended in space. From this we can
conclude that a composite of such magnitudes is a whole of
spatially extended, i.e., materi a l, parts5.
Now for the biology. In two of his biological works, Parts of
Animals 2.1 (646a12-24) and in Generation of Animals 1.1
(715a8-15), Aristotle distinguishes three types of composition
(sunthesis). He arranges these three types of composition hier-
archically in order of increasing complexity (cf. Bogen, 1996: p.
183). At the highest level there are objects like living animals
and at the lowest level there are the four elements from which
all other material objects are composed.
At the lowest level on the hierarchy we find the composition
that occurs between the four elements—earth, air, fire and wa-
ter (Parts of Animals: 2.1.646a12-13). When these elements
have been mixed the result, as we’ve already seen, is a ho-
moeomerous composite whose smallest parts have the same
character as the whole.
At the next level up on the hierarchy are those parts which
result from combining the homoeomerous parts. The non-uni-
form or anhomoeomerous parts which result are not divisible
into smaller parts which have the same character as the whole.
Combine some flesh, bone, blood and sinew in the right way
and you’ve got a toe, for example. Unlike water, the smallest
parts of which are still water, a toe is not divisible into smaller
parts of the same character as the whole. The smallest part of a
toe is not a toe. So at the second level of composition, the ho-
moeomerous parts combine to form the anhomoeomerous parts
of the body6.
At the highest level on the hierarchy are living animals, com-
posed of both homoeomerous and anhomoeomerous parts
(Parts of Animals: 2.1.646b11-13). The mixture of elements
results in flesh, bone and the other organic homoeomeries. The
composition of these parts results in organs, limbs and the other
anhomoeomeries. The whole living animal is composed of all
the parts at the lower levels.
Under what conditions, one might wonder, are these parts
correctly fitted together such that they result in a living animal?
What is the criterion of correct arrangement for a living body?
To answer this, consider the lyre once more. The wood and
strings of the lyre have been arranged correctly when the strings
have been properly tightened and the wood adequately opposes
this tension. In addition, the strings have been properly ten-
sioned when they have been tuned to a particular musical mode.
The parts of a lyre have been harmoniously arranged when the
lyre is able to be played. The criterion for the correct arrange-
ment of the parts of a lyre consists in “its aptitude for perform-
ance” (Barnes, 1982: p. 491). The parts of the lyre are correctly
arranged when the lyre can perform its intended function. The
parts of the body are correctly arranged when they have been
fitted together in such a way that the body can perform its vital
The vital functions of a living human body are things like
self-nutrition, perception, locomotion and thought. So if the
parts of a human body are correctly arranged, the body will be
able to carry out these functions. But now this begins to sound
very much like Aristotle’s view that the soul is the “first actual-
ity of an organized natural body” (On the Soul: 2.1.412b5). We
might say that this organization just is the correct arrangement
of the parts of the body. An organized natural body is one
composed of parts able to carry out the vital functions of the
organism. We’ve just seen, moreover, that an animal body is
composed of homoeomerous and anhomoeomerous parts. So
when these parts are structured so as to carry out an animal’s
vital functions, they are organized correctly. If the criterion for
the correct arrangement is the capacity for the parts to carry out
the vital functions of a living organism, then it’s easy to see
why confusion arose between this and the harmonia theory. I’ll
return to this issue be lo w.
Restating the Alternatives
Now Aristotle’s initial presentation of the harmonia theory
can be restated with more clarity. He had suggested that a har-
monia is either a ratio of the things mixed together or a com-
posite. We now see that he means a harmonia is eith er:
1) The ratio or proportion according to which the four ele-
ments in the homoeomerous parts of the body have been mixed;
2) The composite of spatially extended parts yielding either:
a) the anhomoeomerous parts of the body or b) the body of an
organism capable of carrying out a certain set of vital functions.
But these present two problems for Aristotle. His strategy to
defeat the harmonia theorist was first to spell out the two ways
the theory could be specified and then to argue that it is not
possible for the soul to be a harmonia on either specification.
For this strategy to be successful, the alternatives presented
need to be exhaustive. I think it is clear, however, that the
choice between 1) and 2) does not constitute an exhaustive
disjunction. There are ways of being a harmonia which do not
meet either description. For example, the tuneful blending of
high and low notes constitutes a musical harmonia (Timaeus
80b)7. But even if we were to suppose that 1) and 2) did consti-
tute an exhaustive disjunction; 2’) b) appears indistinguishable
from Aristotle’s positive view about the soul.
4More precisely the argument has to do with the kinds of motion souls and
magnitudes can undergo. Every magnitude can be moved in its own right
(kath hauto, i.e., directly, On the Heavens: 1.2.268b15-16; Physics: 8.6.258b-
24-26). The soul can only be moved on account of something else being
moved (kath heteron i.e., indirectly, On the Soul: 1.3.405b31-406b25).So the
soul cannot be a magnitude. The distinction between direct and indirect mo-
tion is an important one, but the distinction doesn’t make a difference for the
5I will use the expression ‘material parts’ to pick out the same thing as “spa-
tially extended parts”. Aristotle himself allows that there is a kind of matter
which isn’t spatially extended namely, intelligible matter. In Metaphysics:
Z.10.1036a9-11, for example, he describes objects of mathematics as com-
ounds of form and intelligible matter. Such objects are neither spatially
extended nor perceptible. We can leave to one side this curious and conten-
tious matter, however, since Ari sto tl e’s present worry is about magnitudes.
6See also Histor
Having distinguished the two ways he thinks the harmonia
theory can be specified, Aristotle offers no less than four (and
perhaps five) arguments meant to defeat it (On the Soul
1.4.407b32-408a18). He deploys a barrage of arguments against
the theory and it is not always clear where one argument ends
and another begins. What he does say is compressed and some-
7Aristotle refers to Plato’s Timaeus at On the Soul 1.3.406b26 ff.,just prior
to his attack on the harmonia theory of the soul. So it’s fair to assume fa-
miliarity w ith th e dialogue.
Copyright © 2013 SciRes. 49
D. J. YOUNG
times cryptic. Although all these arguments merit philosophical
consideration, let us consider his strongest and most detailed. It
is worth seeing the argument in full:
Further, if we use the word “harmonia” we do so according
to two applications: the most proper is about magnitudes that
have motion and position, a harmonia is a composite of them
whenever they’ve been so fitted together that they admit noth-
ing of the same kind; and then there is the ratio of the things
mixed together—in neither case is it reasonable to apply the
term to the soul, and the application according to which the
soul is a composite of the parts of the body is exceedingly easy
For there are many composites of parts and they are vari-
ously composed. And so what composite of which parts should
one take the mind to be? How is it composed? And what about
the faculty of perception or appetite? And it is similarly absurd
for the soul to be a ratio of the mixture; for the mixture of ele-
ments in flesh is not the same as that in bone. And so it would
follow that the body has many souls all over, since all its parts
are composed of elements mixed together and the ratio of the
mixture is a harmonia that is, a soul (408a5-408a18).
Aristotle’s argumentative strategy is clear. A harmonia is ei-
ther a composite or a ratio. Since the soul can be neither of
these, the soul cannot be a harmonia. The argument then begins
by explaining the disjunction he faces in the first premise.
Aristotle suggests that the word “harmonia” has two appli-
cations. The most proper application of the term is to pick out
“magnitudes that have motion and position” (408a6-7)8. Ac-
cording to this application of the term, a harmonia is an ex-
tended, material composite. More specifically, it is a composite
of spatially extended parts which could either be the anho-
moeomerous parts of the body or the body of an organism ca-
pable of carrying out a certain set of vital functions. “Harmo-
nia” is used in its secondary application to pick out the ratio of
the things mixed in the body (408a8-9). Understood in this way, a
harmonia is the ratio according to which the four elements are
mixed in the homoeomerous parts of the body. That is, it’s a
mathematical property. Aristotle takes these as exhausting the
possibilities—and the soul, he claims, can be neither.
The First Horn: The Soul Is a Composite
On the first horn of the dilemma, Aristotle targets the view
that the soul is a harmonia understood as a composite of the
parts of the body. He’s rather dismissive of it, claiming that the
view is “exceedingly easy to refute” (408a10-11). As I’ve ar-
gued, this specification of the harmonia theory expresses a
materialist thesis: the soul is composed of material parts put
together in a particular arrangement. This materialist thesis can
be specified in three ways, given the hierarchical model of
composition described above9.
1) A harmonia is one of the homoeomerous parts of the body
such as flesh and blood. These material composites result from
mixing earth, air, fire and water.
2) A harmonia is one of the anhomoeomerous parts of the
body such as toes or eyes. These material composites are com-
posed of the homoeomerous parts.
3) A harmonia is the living creature itself. This material
composite having both homoeomerous and anhomoeomerous
Despite Aristotle’s confidence, it is not clear which specifi-
cation of the theory (if, in fact, he did have a particular specifi-
cation in mind) the argument is directed against. All he actually
does to refute it is to note that there are many different compos-
ites of the body and then ask: Which one is the mind or percep-
tion or appetite?
If we lean on his claim that there are many composites of the
body and they are composed in a variety of different ways
(408a11-12), we might suppose the argument is directed against
the first two sorts of composite. His qualms have to do with
numbers: there are many composites of the body and they are
composed in different ways. There is only one soul10. If the
soul were a composite—a homoeomerous or anhomoeomerous
part of the body—which one would it be? It is absurd to sup-
pose that the soul is any particular composite of the body. He
concludes that the soul is not a composite and so not a harmo-
nia on this specification.
But consider how the argument would run if it were directed
against the view that the soul is a composite of the third sort,
namely, the living body itself. If the soul were such a composite,
the parts of the soul would be the parts of the living body. The
parts of a living body are its homoeomerous and anhomoeo-
merous parts. Aristotle describes the parts of the soul quite dif-
ferently (Sorabji, 1975: p. 43). Faculties like the intellect, per-
ception and appetite are the sorts of parts he ascribes to the soul
The parts of the soul, Aristotle argues, could not be identical
the parts of the living body. His argument consists of rhetorical
questions meant to show the absurdity of assuming otherwise.
Which composite, Aristotle asks, might the mind or perception
or appetite be? No particular homoeomerous or anhomoeomer-
ous part could properly answer this question. Perception is not
identical to flesh or the eyes or the ears. Nor are (all) the parts
of the soul composed of the parts of the body. At 408a12 Aris-
totle asks: How would the mind be composed? The mind, he
will later argue explicitly, cannot be composed of material parts
(3.4.429a10-429b9)11. Since the parts of the soul cannot be
identical to or all composed of the parts of the body, the soul
cannot be the living body. And since the living body is a top-
level composite and such a composite is a harmonia, the living
body is a harmonia. Putting this all together Aristotle can con-
clude that the soul cannot be a harmonia.
There is a problem, however. By assuming that the faculties
of the soul must be certain material composites in the body he
ignores a plausible alternative. It seems that various faculties
and functions of the soul might not be any particular composite.
10This would have to be a n implicit, though not unreas onable, assumption on
Aristotle’s part. He argues against the view that the soul is a ratio using just
this principle. See below.
11The argument for why the intellect lacks a bodily organ is interesting and
controversial. Very briefly the argument runs as (roughly) follows: there
isn’t anything the intellect cannot understand. If the intellect had a bodily
organ or were “mixed” with material elements, then there would be things
the intellect couldn’t understand. So, the intellect doesn’t have a bodily
organ and is “unmixed” with the body. For a sympathetic reconstruction o
this argument see Aquinas’ In Aristotelis Librum De Anima Commentarium:
8One might wonder why Aristotle considers this the most proper application
of the term. Aristotle explains that we acquire first principles by first per-
ceiving particular things which are “better known to us” to understanding
universals which are “better known in themselves”. See, for example, Phy-
sics: 1.1.184a16-20 and Metaphysics: Z.3.1029b3-12. Since perceptible, mate-
rial objects are “better known to us” the primary application of “harmonia”
belongs to these things. A shift in use from concrete to abstract is described
by (Ilievski, 199 3) and (Meyer, 1932).
9In The Sec o n d Alternativ e: A Composite.
Copyright © 2013 SciRes.
D. J. YOUNG
Rather such functions might ontologically depend on the mate-
rial composites out of which the body is composed, without
being identical to them. There are a wide variety of such de-
pendence relations which might obtain between the faculties
and functions of the soul and the material composite—the liv-
ing body or its anhomoeomerous parts—upon which they de-
pend12. In fact, the harmonia theory he’s arguing against seems
to provide just such a relation. The tuned state of the instrument
depends on the material parts of the instrument but isn’t identi-
cal to those parts. If this is the case, Aristotle simply begs the
question against the harmonia theorist: perception and appetite
might ontologically depend on material composites, but are not
identical to or composed of them13.
The Second Horn: The Soul Is a Ratio
On the second horn of the dilemma, Aristotle argues that the
soul is not a ratio of the parts mixed together. The argument is a
straightforward reductio ad absurdum. If the soul were a ratio
of the parts mixed together, it would be the ratio according to
which the homoeomerous parts of the body are composed.
We’ve seen why this is the case above. But the body is com-
posed of a variety of such parts. Flesh, bone, blood and sinew
are some of the examples he mentions. Were the soul a ratio of
the elements of these parts, there would be as many souls as
homoeomerous parts. But it gets worse. According to the hier-
archical model of composition, the anhomoeomerous parts are
composed of the homoeomerous ones. So not only does the
body have more than one soul, but even the anhomoeomerous
parts of the body have as many souls as they have parts. Since
Aristotle assumes that one cannot attribute more than one soul
to an individual (let alone attributing more than one soul to
one’s toe) he concludes that the soul cannot be a ratio.
With this, the dilemma is complete. A harmonia is either a
composite or a ratio of the things mixed. In either case a har-
monia cannot be identical to the soul. There are two problems
with this argument, however. First, the argument against the
first disjunct isn’t sound. Contrary to one of its premises, it is
possible for there to be faculties of the soul which ontologically
depend on, but are not identical to, the material composites of
the living body. Second, the choice between a harmonia as a
composite or as a ratio of the things mixed is not exhaustive.
There are structures which are not ratios or composites as Aris-
totle conceives of them. Simply put, Aristotle dismisses the
harmonia theory with an offhandedness it is not clear he is
entitled to enjoy—not only does the argument he presents con-
tain a false premise, it’s also invalid.
The Relation between the Soul & the Body
If Aristotle doesn’t think the soul is a harmonia, what does
he think it is? It is well known that he understands the relation-
ship between the soul and the body to be special case of the
relationship between form and matter—the soul is the form of
the body. I will now try to show that Aristotle is committed to
the view that the living body is a harmonia of which the soul is
Let us begin, then, with Aristotle’s definition(s) of the soul in
On the Soul 2.1. There he presents three definitions, or better,
three versions of the definition of the soul (Ac krill, 1973: p. 65).
The soul is either:
1) The form of a natural body that is potentially alive;
2) The first actuality of a natural body that has life poten-
3) The first actuality of an organized natural body14.
To understand what sort of body it is that Aristotle claims the
soul is the form of, we’ll need to examine what these various
expressions mean. What does it mean to say that something is a
“natural body that is potentially alive” or a “natural body that
has life potentially” or an “organized natural body”? Aristotle
intends these expressions to have the same referent. A natural
body that is potentially alive is an organized natural body.
Since these expressions are equivalent, Aristotle is making
three claims about what sort of body the soul is the form of—a
body that is natural, potentially alive, and organized.
First, the body is natural. A natural body, quite reasonably, is
a body with a nature. In Physics 2.1 Aristotle explains that “the
nature is the shape and form of things that have within them-
selves a principle of motion and rest; the form is not separable
except in account” (193b4-5)15. What distinguishes a living
body from an artifact is that the former has within itself an “in-
ternal principle of motion and rest.” So a natural body is one
which has a form, but a form which is responsible for the mo-
tion and rest of the animal it informs.
Second, Aristotle claims that the body is potentially alive.
Seemingly paradoxically, it turns out that this does not mean
that the body can come to be alive. Rather, it means that the
body is an actual, living body with all of the proper vital ca-
pacities. He claims: “the sort of body that is potentially alive is
not one that has lost its soul, but one which has it” (412b6).
To see what he means, we need to call upon Aristotle’s dis-
tinction between the levels of potentiality and actuality16. Con-
sider the capacity for walking. When a person is actually walk-
ing, she is said to be at the level of second actuality with re-
spect to this capacity. A person who is able to walk, but who is
not actually walking, is said to be at the level of first actuality
with respect to this capacity. Aristotle also calls this second
potentiality. An infant who is not yet able to walk is said to be
at the level of first potentiality with respect to this capacity.
When Aristotle says that a body is potentially alive, he could
either mean that the body is at the level of first or second poten-
tiality with respect to that capacity. A body at the level of first
potentiality is a body in name only, according to Aristotle. Just
like an axe which no longer has the capacity for chopping wood
is an “axe” only in name, so also a body which no longer has
12Metaphysicians of mind have c atalogued a numbe r of ways the mi nd might
depend on, without being identified with, a composite material object. Non-
reductive physicalists, for instance, deny that the mental and physical are
identical but insist that any mental change requires an underlying material
change. See (Caston, 1997) for an excellent discussion of the harmonia the-
ory as a non-reductive physicalis t account of the mind-body relation.
13As I argue below, on Aristotle’s own view the soul in some sense depends
on the material body, though it is not identical to it. What’s odd is that he
doesn’t explicitly consider this view in connection with his discussion of the
14Options 1 a n d 2 are foun d at 412a20- 21; option 3 at 412a20-21.
15Although Aristotle here claims that the form, and so the soul, is separable
only in account. There is evidence in On the Soul which suggests that part o
the soul—the active intellect—might be capable of existing without the
body. See, for example, 2.1.413a3-9, 2.2.413b24-28 and 3.5 especially
430a22-25. Although this evidence is not uncontested, Aristotle at least
allows the possibility that the active intellect is separable bothin account
and in space.
16On the Soul: 2.1.412b6-413a3; Physics: 3.1.201a10 -201b15.
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D. J. YOUNG
the capacities necessary for living is a “body” in name only (On
the Soul 2.1.412b10-413a5). But a body capable of self-nutria-
tion, perception and self-motion is an ensouled body (Barnes,
1975: p. 33). So a body that is “potentially alive” is one which
is ensouled—it is at the level of second potentiality with respect
to the capacities for living. The soul is the first actuality of that
sort of body.
The structure of this sort of body is explained by Aristotle’s
third claim: the body is organized17. A body which is capable of
supporting nutrition, perception and motion (and perhaps un-
derstanding), is one which has a very particular structure. The
parts of the body must be arranged such that the animal is able
to perform these various vital functions. Such a functionally
organized body is essentially ensouled. A body without a soul
is a “body” in name only. As we’ve seen, the soul is the form of
the body—it explains why the body is composed and organized
as it is. That it doesn’t explain what sort of structure is capable
of carrying out the animal’s vital functions.
But we do know how the functionally organized body is
composed from the hierarchical model of composition pre-
sented in the biological works18. We’ve seen that Aristotle de-
scribes three levels of composition. Mixtures are the result of
combining the four elements. These homoeomoerous parts of
the body (e.g., flesh, bone, blood and sinew) combine to form
more complex parts like fingers and toes. Put all these parts
together in the right way and you’ve got an animal body; one
structured such to carry out the animal’s vital functions. The
organized living body is the most complex biological compos-
ite. And this means that the “organized natural body” just is a
In rejecting the harmonia theory, Aristotle presented two
possibilities: a harmonia is either the ratio of the things mixed
or a composite. He argues that the soul is neither of these. But
given the model of composition in the biological works, he is
committed to the view that the functionally organized body is a
material harmonia. And so, I suggest that we ought to under-
stand Aristotle’s definition as follows: the soul is the form of a
An Objection and Reply
Some have objected to this line of argument by claiming that
Aristotle things the soul is identical to the functionally organ-
ized body (Irwin, 1988: p. 285; Whiting, 1992: p. 81). If the
soul and the living body are identical, then Aristotle has unwit-
tingly committed himself to the version of the harmonia theory
he rejects outright. I will show that the evidence does not show
that the soul and functional body are identical, rather they are
two constituents parts of a unified whole.
Here is the evidence appealed to which purportedly shows
the identity between the soul and the functionally organized
[I]t’s not necessary to ask if the soul and the body are one,
just like its not necessary to ask it the wax and the shape are,
nor generally about the matter of each thing and that of which
it’s the matter (412b6-9).
So in whatever way form and matter are one, the soul and the
body will also be one. This view is supported and explained in
an important, though murky, passage in Metaphysics H.6 (Ross,
1953). There we find the following:
As we’ve said, the proximate matter and the form are the
same and one—the former potentially, the latter actually so
that the search for the cause of the oneness is like the search
for their being one. For each thing is one, and the potentiality
and the actuality are in a way one... (1045b17-21).
Let me clarify the terminology here. Aristotle distinguishes
different types of matter, in part, by differences in their persis-
tence conditions. The persistence conditions for some types of
matter are determined according to their level of organization.
Some material parts survive the death of the organism19. That is,
their identity as the sorts of parts they are is not determined by
the whole of which they are parts. Aristotle writes: “the clay
statue is destroyed into clay, the bronze sphere into bronze and
Callias into flesh and bones” (Metaphysics: Z.10.1035a31-33).
The flesh and bone into which Callias is destroyed is his “re-
Some material parts of an organism, however, cease to exist
when they’re no longer parts of a functioning whole21. Their
persistence conditions are bound up with their being function-
ing parts of a living organism. The “proximate” matter of a liv-
ing creature persists only so long as it can fulfill its function. A
finger or an eye is what it is only while it is part of a function-
ing whole. For Aristotle, a severed “finger” or the “eye” of a
corpse is a finger or an eye in name only. These organic parts
are the proximate matter of the living organism.
Aristotle broadens this claim: “We must apply to the whole
living body that which applies to the part” (On the Soul:
2.1.412b22-23). From this it seems reasonable to take the whole
organic body as the proximate body of the organism. Just as a
stone or painted “eye” lacks the capacities characteristic of a
real, functioning eye and so is an eye in name only; so also a
dead body lacks the capacities characteristic of a functioning
organic body. Hence he claims that the organic body is essen-
tially ensouled. Again, “it is not the body that has lost a soul
that has the potentiality to live, but the body that has it”
(412b25-6). The body that has a soul has the right sort of ca-
pacities for living and does not survive the death of the organ-
ism. That sort of body serves as the proximate matter of the
living organism. The body that lacks a soul lacks the capacities
for living and can survive the death of the organism. But the
“body” that lacks the soul is just a heap of elements—the re-
mote matter which persists after the death of the organism.
To this point, I’ve shown the evidence suggesting that the
soul and body are one in the same way as the wax and its shape
are one. Also, I’ve shown that the proximate matter—which we
should now understand as the functionally organized body—
and the form are “the same and one”. But does this mean that
the soul and the body are identical?
The Same and One...
Aristotle occasionally uses the expression “the same and
one” to mean identity, as we do in English (White, 1971: p.
178). Uncontroversially, identity is that relation which holds
19On the Soul 2.1. 4 1 2b25- 26 ; Metaphysics Z.10.1035a18-19.
20The talk of proximity or remoteness has to do with the metaphorical dis-
tance the matter is from the target form. This ‘distance’ is to be accounted
for by the difference in degrees of organization—something with a higher
degree of complexity inits organization is further from something with a
lower degree of complexity.
21On the Soul 2.1.412b13-15; 412b20-22; Parts of Animals 1.1.640b35-
641a6; 1.5.645a35; Metaphysics Z.10.1035b18-27; Z.11.1036b30-3 2.
17This sometimes gets rendered “a body with organs” or “an organic body,”
but calling the body organiz ed seems to do just as well.
18Parts of Animals : 2.1.646a1 2-24; Gene r ation of Animals: 1.1.715a8 -1 5.
Copyright © 2013 SciRes.
D. J. YOUNG
between a thing and itself. Aristotle sometimes uses the phrase
to pick out this relation. For example when investigating the
one-over-many problem in Metaphysics Z.14 he asks whether
“the animal in horse is one and the same as the animal in man
as you are one and the same as yourself” (1039a33-34). Though
here he uses “one and the same” to express identity, he doesn’t
always do so.
In his philosophical lexicon, Metaphysics D.6, Aristotle out
lines no less than ten different ways we might say that some
thing(s) are one; and in D.9, he mentions three things one might
mean by “the same”. I won’t list them all here. Suffice it to say
that not every combination of “one” and “the same” expresses
the identity relation. I propose that we ought to understand
Aristotle’s claims about the oneness of form and matter as a
claim about composition and not identity. When he says that
form and matter are the same and one, he means that form and
matter are the metaphysical parts which together compose a
single, unified whole.
The first step in understanding the oneness of the soul and
proximate body is to look at Aristotle’s account of oneness by
continuity, one of the senses distinguished in the philosophical
lexicon. The word that gets translated as “continuity,”
“sunechê,” is rendered just as well by “held together”. There is a
sort of unity, Aristotle claims, between some things when they
are held together (D.6.1015b36-1016a1). What makes it the
case that some things are held together is not just that they are
merely in contact, as the parts of a heap might be. Rather, some
things are held together just in case they have been worked up
into a whole. Some things can be worked up into a whole by
craf t, other things by nature.
We distinguish, along with Aristotle, between a heap of stuff
and a whole of parts. A whole is distinguished from a heap in
as much as the parts of the former have been structured in some
principled way. The bits of leather in a pile before the cobbler
practices her craft are unstructured; but after they’ve been
properly cut and stitched, they’ve been worked up into a struc-
ture—a shoe. The various bits of leather are one, i.e., parts of a
whole, because they’ve been united under a single form by the
skill of the cobbler. The form so imposed is the reason why the
parts are held together and are not in a heap. Some things
achieve such a condition by nature. A plant has within itself the
cause of its own continuity. Plants are not put together like
shoes. Aristotle vividly describes how the elemental parts of a
plant are prevented from flying apart by the soul:
Further, what is it that holds together (to sunechon) the fire
and earth when they are moving in opposite directions? For
they will be torn apart unless something prevents it; if there is,
it will be the soul... (On the Soul: 2.4.416a6-8).
Because plants are not constantly bursting apart into their
elemental constituents, we can presume that the soul is the uni-
fying form which holds the parts together. A plant is a whole of
parts held together by the soul. Aristotle defines “a whole” as
something that “contains its contents in such a way that they are
one thing” (Metaphysics: D.26.1023b27-28). A plant contains
its contents in just this way. So what we have is the following
account of the oneness of the soul and the body: the soul and
body are one in virtue of the fact that they jointly compose
something (i.e., the living thing) w h ic h is on e.
Though they still count as being “one” by being parts of a
whole, form and matter are different. Aristotle clearly ascribes
different, and sometimes incompatible, properties to the soul
and the body. To list a few, without comment: a form is the
same as its essence, but matter is not (Metaphysics: Z.11.1037-
a34-b7); forms are substances rather than or more than matter is
(Z.3.1029a29-30); forms are definable, but matter is not (Z.11.
1036a28; 1037a27-31). Examples of such differences are easy
to multiply. By a simple application of Leibniz’ Law, forms
have at least one property that matter lacks and so the two can’t
Moreover, I wish to argue that for Aristotle “soul” and
“body” have different referents. There is not a single subject
which might be picked out by “soul” and by “body.” Rather
“soul” picks out the structure in virtue of which some material
parts compose a whole (something which is itself non-material);
while “body” picks out the material parts so structured (some-
thing material). In this way, soul and body are parts of a whole
(albeit parts in different senses) of a single thing—a living or-
There is good reason to suppose that Aristotle held this view:
The syllable is not just its elements—BA is not the same as B
and A—nor is flesh just fire and earth. For on dissolution the
flesh and the syllable no longer exist, but the letters exist, and
so do the fire and the earth. So the syllable, then, is not only the
elements (the vowel and consonant), but something else besides
He explains later that this something else is not an element,
nor is it composed of elements (1041b25-27). Aristotle is clear
about this much at least: in the case of a whole of parts, the
whole is a unity, composed of elements and “something else”
of a different character. This “something else” is not an element
or composed of elements, on pain of regress. This “something
else” he describes as “the substance of a particular thing”
We know from Metaphysics Z that the substance of a par-
ticular thing is its form. The form is the principle in virtue of
which something exists as the sort of thing it is and not some-
thing else—its structure. The form is the reason why some earth,
air, fire and water are a human being and not a chair. For these
elements to be unified into a whole, a form needs to be present.
The form is not an element, but a property and, as it turns out,
is described as a part of a composite living thing. To appeal
again to Aristotle’s lexicon, he defines “part” in a number of
ways. The relevant one is that a part “is that into which a whole
is divided or out of which it is composed, either the form or that
which has the form, for example the bronze (this is the matter
in which the form is) is a part of the bronze sphere or cube and
the angle is a part” (Metaphysics: D.25.1023b19-22). So the
form and matter are parts of a single composite. The soul uni-
fies the material parts of the composite, though it is not material
or composed of material parts. The form is responsible for the
unity of the material parts, a role it couldn’t play were it some-
thing material .
In sum, Aristotle’s claims about the “oneness” of the form
and matter or the soul and body are claims about the unity of
22Aristotle’s analysis of form and matter is as contentious as it is obscure. A
detailed discussion of this controversial issue is beyond the scope of this
aper. I don’t suggest that these considerations are decisive. I am offering
one way to trace a line of argument which accounts for Aristotle’s appar-
ently conflicting accounts of the soul and body. For related discussion of the
non-identity of form and matter, soul and body see for example (Wedin
2000), especially chapter 8; (Code and Moravcsik, 1992); and (Shields,
Copyright © 2013 SciRes. 53
D. J. YOUNG
Copyright © 2013 SciRes.
distinct metaphysical parts into a whole. The form generally or
the soul specifically is the principle according to which some
material parts are structured. Though this principle is not an
element or composed of elements, it is still properly understood
as part of a whole—albeit a part of a very different sort than the
material parts so structured.
There are different versions of the harmonia theory. Aristotle
considers two very narrow specifications: a harmonia is either a
ratio of certain parts of the body or it’s a material composite,
namely, the living body. Thus he is able to reject both of these
without, thereby, undercutting his view that the soul is the form
of a living body. The reason for the perplexity of Aristotle’s
commentators is that it turns out that he’s committed to a ver-
sion of the view he’s trying to refute. He rejects versions of the
harmonia theory, but in the end the view he accepts is itself a
harmonia account. By carefully distinguishing and arguing
against the versions of the theory he finds objectionable, Aris-
totle is able to accept what the harmonia theory gets right
namely, that the soul is the structure of the living body.
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