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δὲ θλάσις ἐκ βάρους, ἡ δὲ διάβρωσις ἐκ δακνώδους γίνεται ποιότητος.
ὅταν οὖν ἔξωθεν μὲν μηδὲν ᾖ τὸ τεῖνον ἢ βαρῦνον ἢ δάκνον, ἐξ ἑαυτοῦ δέ τι
πάσχῃ τούτων τὸ σῶμα, παντί που δῆλον ὡς ἡ μὲν τάσις ὑπό τινος ἔνδον
οὐσίας πολλῆς διατεινούσης τὸ περιέχον αὐτὴνσῶμα γίνοιτ᾿ἂν ἢἀμέτρου
ξηρότητος, ἡ δὲ θλάσις ἔξωθεν ἐπιπεπτωκυίας οὐσίας σκληρᾶς ἢ μεγάλης ἢ
βαρείας ἢ συναμφοτέρων, ἡ δὲ δῆξις ὑπὸ χυμοῦ δακνώδη φύσιν ἔχοντος·
ἐπισκεπτέον οὖν ἡμῖν ἐνταῖς σφοδραῖς ὀδύναις ἤτοι χυμὸν πολὺν ἢ πνεῦμα
διέξοδον οὐκ ἔχον, ἢ βαρὺν ὄγκον, ἢ δακνῶδες ὑγρὸν ἢ διάθεσιν ξηράν· ἔτι
δὲ πρὸς τούτοις, ὡς ἐν ἀρχῇ διῄρηται, τὸ θερμαῖνον ἰσχυρῶς ἢ ψῦχον. ὧν
πάλιν αὐτῶντὰςαἰτίας ἢἐντῷ πνεύματι θετέον ἢἐντοῖς ὑγροῖς ἢἐντοῖς
στερεοῖς· ὅ τι γὰρ ἂναὐτῶν ἰσχυρῶςψυχθὲν ἢὑποθερμανθὲν ψαύῃ τῶν
πλησιαζόντων, ὀδυνηρὸναὐτοῖς γίγνεται.
First, let us look into what the nature of that which will divide continuity
must be. It is, of necessity, a rupture, contusion or erosion – that is, a
condition in which a continuity is divided. But rupture arises from some
tension, contusion from a weighing down and erosion from a biting quality.
Therefore, when there is nothing external stretching, weighing down or
biting and yet, of itself, the body suffers one of these, it is surely clear to
everyone that tension arises when the body is stretched significantly by
some large substance which it contains within, or by excessive dryness;
contusion arises when a hard, large, or heavy substance, or all of these
together, has impinged on it from without; gnawing arises due to a humour
which has a biting nature. What we must consider, then, in severe pains is
either abundant humour, or pneuma not having a path out, or a heavy
mass, or a biting fluid, or a dry condition. Over and above these are severe
heating or cooling, as I distinguished at the start. We must, in turn,
establish the causes of these same things, either in the pneuma, or in the
fluids, or in the solid [parts] because, if one of those that has been strongly
cooled or heated touches the parts adjacent, it generates pain in them.
This extensive aetiology of pain includes not only the bodily humours
but also obstructed pneuma, heavy masses, biting fluid, a drying condition
and severe heating and cooling.
The causes of these conditions,
according to Galen, are to be found respectively in the pneuma, bodily
fluids and solid parts.
When these are cooled or heated excessively, they
make contact with adjacent parts, generating pain. Extremes of tempera-
ture presumably affect the size of certain masses. A heated tissue expands
(becoming finer and more loose-textured), owing to which it takes up
more space than usual. The ultimate cause of the phenomenon of pain in
MM . (.–K), tr. Johnston and Horsley (: ).
It is worth noting that the shorthand explanation for how humours cause pain only mentions
‘abundance’, unlike in HNH . (.K) cited earlier.
For a discussion of these three kinds of substances as foundational to physiology, Section ...
Perception and Voluntary Motion
this case is the touching of two parts that would not touch under normal
circumstances. Thus, pathological touching originates from excessive
heating or cooling.
It is also worth noting that these explanations are
therapeutically relevant. Given that Galen advocates for an ‘opposites-heal-
opposites’ methodology,
knowing that pain is caused by, for instance,
heating, is indispensable to its treatment. There is, arguably, no inherent
inconsistency between the causes of pain, as described in the passages of
On the Therapeutic Method, and the commentary on Hippocrates’ On the
Nature of Man. The former therapeutic treatise provides an exhaustive
account, while in the commentary, Galen only mentions the part of the
phenomenon of pain that is contextually relevant.
The second cause of pain, namely change, is discussed brieflyinOn the
Therapeutic Method, but a more elaborate treatment of this topic can be
found in a different treatise, the commentary on Hippocrates’ On
Elements. At the beginning of this treatise, Galen presents an elaborate
discussion of the phenomenon in a polemical context, thereby clarifying
not only why change is one of the two causes of pain but also what is at
stake in his theorisation about this phenomenon.
.. Pain Requires Plurality: The Concept of an Element
The notion of the element is crucial to Galen’s argument. The very first
sentence of this treatise presents a working definition: an element is the
least of the thing of which it is an element.
Galen then qualifies this
claim, stating that elements are not the smallest perceptible parts, owing to
which sense perception is not a judge of elements. Although it brings to
mind the empiricist method, which relies solely on sense perception,
this
part of the definition rules out treating the limbs and organs as elements in
general. Galen’s argument consists in a kind of reductio ad absurdum,
reminiscent of one of the Pyrrhonian Modes.
He notes that animals
with keen vision, such as eagles, would be able to discern different (and
presumably, finer) elements than those that humans are capable of
An interesting illustration is the cases when pain does not occur thanks to the brilliance of human
body design. Take, for example, the way in which tunic does not produce pain by touching the
lens due to soft, spongy material, UP . (., –H¼.–K).
MM . (.K).
Hipp. Elem. . de Lacy (.K), tr. de Lacy (: ). See also PHP ..– de Lacy (.K).
To be precise, experience acquired through sense perception; see MM . (.K); Frede
(: ).
See Sextus Empiricus PH .; .. See Frede () for a discussion of the relationship between
Empiricism and Pyrrhonism.
. Pain and Nerves
perceiving. The sceptical argument excludes there being a ground for
empirical knowledge in general, but Galen does not subscribe to such a
view. Instead, he uses the same kind of argumentative tactic to effectively
eliminate the empirical position in this particular case.
‘Element’ does not, therefore, stand for a limb, nor any discernible
part. It denotes a fundamental constitutive part, which is discoverable by
means of reason. This leads to the question of whether the element is
singular or plural in kind and, in case of the latter, what these kinds are
(in addition to some related issues). For this, Galen turns to Hippocrates
and his proof that the elements are plural:
‘I say that if man were one
thing he would never feel pain, for there would be nothing that would
cause him pain if he were one.’
Galen uses this proof against his target, that is, those who maintain that
there is a singular kind of element. To be precise, the target here is
atomism. Their fundamental particles are the single type of material
accounting for the world’s construction. Galen cites the famous saying of
Democritus that properties such as colour or sweetness are merely ‘by
convention’, whereas, in reality, there are only atoms and void.
It is
worth noting, however, that Galen’s target is most likely not only the
atomists in general, but the medical atomists in particular, especially
Asclepiades of Bithynia and his followers.
Although at the beginning
of the treatise Galen names Democritus and Epicurus as atomists,
the
very same argument is levelled in other works directly against Asclepiades.
Despite Galen’s phrasing, there are some significant diff erences between
such atomists as Epicurus or Democritus and the medical atomists. They
not only differ in terms of the issues in which they were interested, but also
in terms of their respective theories of atomic particles. As Galen notes in
On the Constitution of the Art of Medicine, the anarmos particle (posited by
Asclepiades) is fragile but it is not the cause of pain when it is broken,
Loosely speaking, of course. See Leith () for the discussion of a confluence of influences,
showing that Galen takes the Hippocratic argument aimed at monists and meshes it with the
Peripatetic argument against atomists.
Hipp. Elem. . de Lacy (.K), tr. de Lacy (: ). This claim comes from Hippocrates’ On
the Nature of Man (Nat. Hom. . (, – Jouanna¼ Littré .–)). See also Galen’s HNH .
(.K) and CAM , – Fortuna (.–K).
Hipp. Elem. . de Lacy (.K).
Nutton (a: ) explains that Asclepiades can be seen as the doctor whose work marks the
arrival of Greek medicine in Rome. He was a celebrated doctor with many followers (see –),
which may have made him an especially clear rival to Galen. Later in the treatise, Galen also attacks
the Pneumatists, although then the issue at stake is the nature of elements; see Kupreeva (:
–).
Hipp. Elem. . de Lacy (.K).
Perception and Voluntary Motion
because it is not capable of being affected.
Galen repeats this argument
in On the Constitution of the Art of Medicine. If the element composing
flesh is not capable of being affected, sensation would not be possible; but
there is sensation, therefore the element must be capable of being
affected.
He then remarks that this argument overturns the hypothesis
of atoms – anarma and minina – clearly referring to Asclepiades.
Likewise in On the Therapeutic Method, the inability of atomic particles
to be affected is said to be the fatal shortcoming of the account of pain
posited by those who subscribe to such a view. Galen then refers his
readers to his On the Opinions of Asclepiades, suggesting that Asclepiades
and his school are the targets of his critique.
It is also possible that Galen addresses the followers of Asclepiades more
generally given the phrasing in a passage from On the Therapeutic Method,
which suggests that his opponents admit to their theory’s shortcomings.
He explains that those who subscribe to the view that the body is
composed of atoms correctly claim that it is impossible to find the condi-
tion from which pain results.
This may indicate that Galen’s opponents
were certain contemporary followers of Asclepiades who publicly conceded
their point by the time that Galen composed On the Therapeutic Method.
Galen’s argument against these doctors and philosophers goes as follows:
the atomists posit a single unit as the ‘element’, but this unit is such that it
is unable to be affected. At this point, an atomist, of course, could retort
that an aggregate of atoms produces the phenomenon of sensation.
Therefore, a substantial part of Galen’s attack is focused on showing that
such aggregates would not be able to generate the phenomenon of sensa-
tion either.
He does so by theoretical means, that is, logic,
while
occasionally also invoking appeals to empirical data.
The upshot of his
argument is that, if one atom is not able to be affected, then neither will
two atoms put together, and so forth.
Galen’s refutation here follows
the account of an element that he provides at the beginning of the treatise.
Elements are primary parts of an object, but they are not ontologically
CAM , Fortuna (.K). On the fragility of Asclepiades’ particles, see Vallance ( :
–).
See Caston (: –).
CAM , Fortuna (.K).
MM . (.–K).
MM . (.K).
It has been argued in the scholarship that this argument is also found before Galen, in Plutarch
Adv. Col. B–C; E; see Gemelli Marciano (: ). See also the discussion in Leith
(: –).
See Hipp. Elem. . de Lacy (.K).
Hipp. Elem. . de Lacy (.K).
Hipp. Elem. .– de Lacy (.–K).
. Pain and Nerves
distinct. As Galen later states in the treatise, especially in his discussion of
the differences between the principle and the element, an element is
entirely homogenous with the object that it composes.
If an atom is
an element of an animal (on Galen’sdefinition of an element), then it
must share the properties of the animal.
Thus, Galen rejects elemental ‘monism’ because it cannot account
for the change indicated by the phenomenon of pain. To be more precise,
this leads to the conclusion that the phenomenon of pain requires two
conditions: () qualitative alteration;
and () sensation.
These are
discussed more extensively later on in the treatise, but the discussion of
pain as such is not prolonged beyond the first proof, viz. that there are
many elements. Galen later arrives at the conclusion that a mixture of the
four elements is a likely candidate for explaining qualitative change and
sensation,
which is likewise the phenomenon underlying pain.
.. Pain as a Phenomenon and a Sensation
Sensation, which includes pain and sense perception in general, is a
phenomenon of the tissues, that is, the homoeomerous parts. It is worth
remembering that the other cause of pain discussed earlier, namely the
Hipp. Elem. . de Lacy (.K). The principle is not entirely homogenous with the object of
which it is a principle. The elements, meanwhile, are entirely homogenous: ἐν τούτῳ γὰρδὴ καὶ
διήνεγκεν ἀρχὴ στοιχείου, τῷ τὰςμὲν ἀρχὰςοὐκ ἐξ ἀνάγκης ὁμογενεῖςεῖναι τοῖς πράγμασιν, ὧν
ὑπάρχουσιν ἀρχαί, τὰ δὲ στοιχεῖα πάντως ὁμογενῆ. An element, then, must be the smallest part
of the thing of which it is an element, but it also has to be recognisable as a part (however small) of
that object.
A somewhat strange consequence of this claim is that Galen’s argument does not suggest that the
world per se is not composed of atoms. It merely shows that atoms are not elements. To use Galen’s
own terminology, atoms cannot be elements, but his argument does not rule out the possibility
that atoms could be principles. Thus, the elements of the human body could be composed of
atoms, but atoms themselves cannot be the elements.
Galen is adopting and adapting the Aristotelian notion of alteration here. For a discussion of his
innovations, see Kupreeva ().
Hipp. Elem. .– de Lacy (.–K), tr. de Lacy (: ): τὸ γὰρ ἀλγῆσον χρὴ δήπου
δύο ταῦτα ἔχειν ἐξ ἀνάγκης, ἀλλοιωτόν τε καὶ αἰσθητικὸν ὑπάρχειν. εἴτε γὰρ μηδέποτε μηδεμίαν
ἀλλοίωσιν ἐπιδέχοιτο, φυλάξει διαπαντὸς ἣνεἶχεν ἐξ ἀρχῆς κατάστασιν· οὐ φυλάττει δέ γε τὸ
ἀλγοῦν· εἴτε δέ γε μεταβάλλει, καθάπερ οἱ λίθοι τε καὶ τὰ ξύλα θερμαινόμενα τε καὶ ψυχόμενα καὶ
διαιρούμενα, μὴ παρείη δὲ αὐτῷ τις αἴσθησις σύμφυτος, οὐκαἰσθήσεται τῆς ἀμφ’ αὐτὸ γενομένης
διαθέσεως, ὥσπερ οὐδ’ οἱ λίθοι. ‘Surely something that is to feel pain must necessarily meet these
two requirements: it must be capable of change and capable of sensation. If it never undergoes any
change, it will retain at all times the state in which it was at the beginning; but what feels pain does
not retain it; and if it changes its state, as stones and wood do when being heated and chilled and
split, but no sensation is by nature present in it, it will not perceive the occurrence of the condition
that is affecting it, just as stones do not.’ See also Hipp. Elem. . de Lacy (.K).
Hipp. Elem. . de Lacy (.–K).
Perception and Voluntary Motion
dissolution of unity, also originates in these parts. To answer the first
question raised at the beginning of this section, the nature of pain is such
that it has its grounds in the properties of tissues, including flesh. This
point is in line with Galen’s argument that flesh is even more pain-sensitive
than nerves. At the same time, this leads to the question of whether these
views are also compatible with the claim that pain is one of the three
purposes in distributing the nerves throughout the body, as Galen states in
On the Usefulness of Parts.
There are two ways of approaching this problem. First, one could take
this as a genuine inconsistency that indicates a change in Galen’s views.
Indeed, given his long and prolific career, this is entirely possible. It is,
nonetheless, hard to prove. Thus, it would be best to resort to this
conclusion when all the other possibilities have been explored and
excluded. The second option, however, would be to consider the context-
ual differences, after which we can determine whether the differences
between the two claims are merely apparent.
Most of the discussions in On My Own Opinions are polemical, and the
treatise could reasonably be described as a collection of clarifications.
As Galen explains at the beginning of the treatise, there are people who
misunderstood his works (and thereby, we may presume, criticised him
unduly), much of the treatise is therefore intended as a corrective to those
errors through the clarification and reiteration of his actual position.
In some sections, the debate at stake is very clear. The section on nerves,
however, is less explicit, and primarily describes dissections, concluding
that nerves are not more sensitive than flesh. Arguably, Galen’s way of
framing the discussion at the beginning of the section offers hints about
the broader debate.
The section begins with the claim that the most sensitive part of the
body is that which hosts the hēgemonikon, and from it flows the capacity of
sensation to the rest of the body by means of nerves.
Given that the rest
of the section shows the nerves to be no more sensitive than flesh, the
position under attack here is that the nerves are inherently sensitive and
have the capacity for sensation in themselves. This theory is later discussed
in greater detail. For current purposes, the salient claim here is not that the
nerves are generally less sensitive than flesh, but rather that the nerve
tissues are not inherently imbued with sensitivity. They only obtain this
capacity from their connection to the brain, and this claim is supported by
Prop. Plac. . ( Lami Garofalo): Πρῶτον μὲνγὰραἰσθητικὸν ἐδείξαμεν εἶναι τὸ μόριον, ὡςκαὶ
τοῖς παλαιοῖς ἔδοξεν εἶναι, <ἐν> ᾧιτὸ τῆς ψυχῆς ἡγεμονικόν ἐστιν.
. Pain and Nerves
dissections that reveal the nerves are not more sensitive than flesh. Thus,
the most important claim here very much coheres with Galen’s position in
On the Usefulness of Parts.
On the Usefulness of Parts repeatedly describes the nerves as being
necessary for sensation. In describing the muscles of the hand in Book ,
for instance, Galen explicitly states that sensation is not inherent in the
flesh: nerves have to extend from the brain to render this prehensile
instrument sensitive.
Sensitivity therefore arises from the connection
to the brain by means of nerves. This leads to the following picture of the
phenomenon of pain with regard to the relationship between the brain,
nerves and flesh.
A change in tissues (whether this is qualitative or consists in a change in
unity) constitutes the phenomenon of pain. Nevertheless, it is only
through a connection with nerves that sensations such as pain can be
actually felt. In other words, there can be no sensation of pain without the
nerves, regardless of the sensitivity of the flesh. A loss of sensation at the
ligature of a nerve is an established claim in Galenic corpus,
but the
discussion of the sensitivity of flesh suggests that what does the heavy
lifting on this model is the very distribution of the nerves within the
structure of the body, not any innate properties of the nerve tissue. This
is a potentially significant insight in understanding the systematicity of
Galenic physiology.
Before moving onto the final activity of the nervous system, viz. sense
perception, there is still one remaining question to be addressed: the
relationship between pain and sensation. These activities are evidently
related, but perhaps the reason why Galen separates them is that pain is
a distinct kind of sensation. First, unlike sense perception, pain is not
continuously present. Its presence signifies some kind of disorder. Second,
and more importantly, pain is internally directed. As argued in the discus-
sion of the causes of pain, pain indicates that some pathological event is
taking place in the tissues. It is an inwardly directed perception of a
pathological state within the body.
Given Galen’s understanding of
the body as, to a certain extent, a self-regulating system,
pain affords a
valuable tool for the coordination of body parts with a view to health.
UP . (., Helmreich¼.K).
Form. Foet. , – Nickel (.K); PHP .. de Lacy (.–K). See also Ierodiakonou (:
–).
See PHP ..– de Lacy (.–K), where Galen makes his claim while commenting on
Hippocrates (Aph. . (. Littré)). See also Mot. Dub. .– (, – Nutton).
See van der Eijk (: –).
Perception and Voluntary Motion
. Internal Perception and External Sense Perception
The concept of pain as internally directed sense perception neatly captures
all of Galen’s claims about pain. However, it is important to note that pain
is not the only example of such a perception. This chapter began with his
claim that the three governing parts are also connected by their offshoots
so that they might heed (ἐπαΐειν) each other, followed by the claim that the
nervus vagus is inserted into the liver so that it would not be entirely
without sensation. My discussion of the role that the nerves play in
perception will start with the inward-directed perception before moving
on to the discussion of the sense perception and the problems of the nature
of the nervous tissue.
As well as describing the nerve in the liver as serving a sensory purpose,
Galen makes similar claims about the reproductive organs and the
stomach;
the heart too contains nerves, the significance of which was
discussed earlier in this chapter. These organs lack muscles, owing to
which nerves are not able to move them. In these cases, nerves only serve
the purpose of sensation; and so, his claim about the purpose of the nervus
vagus in the liver is consistent with his anatomical understanding that for a
nerve to exercise control via voluntary motion, an instrument is required.
The sensory role of the nerves in these organs, however, cannot be
extensive, because only a small number of nerves are present. In the case
of the liver, for example, Galen states that a single, small nerve renders the
liver barely sensitive at all.
This claim reflects ordinary experience. The
nerve in the liver simply cannot produce the same sensitivity as, for
instance, the optic nerve, because animals see their environment with great
precision, which is not the case with the liver. It is barely possible to feel
what one’s liver is doing. Internally directed perception, therefore, is quite
distinct from that which is directed externally. The physiological process
underpinning both of them might be the same, but their purposes subtly
differ, meaning they are not univocal.
Galen acknowledges the limitations of the sensory role of these nerves
when he states that internal organs receive some share of nerves in order
that they might not be completely plant-like. However, the liver and heart
receive nerves because they are the sources of certain capacities (διότι καὶ
αὐτὰ δυνάμεών τινων ὑπάρχουσιν ἀρχαί).
In either case, the stakes are
Both female and male reproductive organs; see UP . (., – Helmreich¼.K). UP
. (., – Helmreich¼.K).
UP . (., – Helmreich¼.K).
UP . (., – Helmreich¼.K).
. Internal Perception and External Sense Perception
low: these nerves only need to make the organs more sensitive than the
simplest form of organic life. The claim raises two questions. First, why is
such a limited role sufficient for the healthy functioning of the body?
Second, how can the presence of a nerve elevate an organ from being
merely plant-like?
The second question can be answered easily by referring to the case
discussed earlier in this work. The kind of ‘perception’, described as
γνωρίζειν by Galen, is possessed by plants and bodily tissues has been
discussed in Chapter . There, I argued that this perception is binary, in
the sense that it consists of two reactions: these kinds of entities can only
accept or reject material presented to them. The same chapter also pre-
sented a discussion of the phenomenon of hunger. Galen divided it into
two stages, the physical and the psychic. The physical stage consists of
tissues drawing nutriment from the veins and emptying them, prompting
the veins to draw from the stomach, which in turn uses food as a remedy.
This action does not produce the sensation of hunger by itself. Hunger
arises when the stomach perceives the drawing of veins, which leads to the
proper sensory perception of hunger. Galen divides the whole process into
five parts as follows: ‘First there is the emptying; second is the physical
appetite of the emptied parts; next is the sucking of the stomach; next is
the sensation of this; last of all there is the psychical appetite of this.’
While the text does not include an explicit reference to the nerves, the
fifth and final stage must be enabled by the presence of the nerve in the
stomach, not least because, elsewhere, Galen notes that perception in
organs such as the stomach is grounded in the presence of a nerve.
His distinction between nature and soul makes it clear at what point
sensation is produced, and thereby when the nervous system comes into
play.
Lack of nourishment leads the venous tissues to exercise their
attractive powers.
This leads them to draw from the stomach. The
following step involves sensation in the stomach, as denoted by the word
αἴσθησις. Both language and conceptual apparatus suggests that this is
where the nervous system comes into play. The stomach’s sense perception
must be owing to the presence of a nerve that sends a signal to the brain,
from which results what Galen calls the psychic appetite. Thus, the origin
Symp. Caus. .. (.–K), tr. Johnston (: ): κένωσις μὲν πρώτη, δευτέρα δὲὄρεξις ἡ
φυσικὴ τῶν κενωθέντων μορίων, εἶτα ἡ μύζησις τῆς κοιλίας, εἶτα ἡ ταύτης αἴσθησις, εἶτα ἡὄρεξις
αὐτῆς ἡ ψυχικὴἁπασῶν ὑστάτη. This passage is cited in full in Chapter .
Stated explicitly in UP . (., – Helmreich¼.K).
See UP . (. Helmreich¼.K), cited and discussed earlier.
See Nat. Fac. .– ( Helmreich¼.K).
Perception and Voluntary Motion
of sensation is the point at which physical appetite changes into a psychic
one. The former is the change within the tissues, caused by a lack of
nourishment. It turns into the latter when a nerve in the stomach registers
the changes in its tissue and sends this signal to the brain, which results in
a desire for food (and not just – it is worth noting – awareness of lack).
This passage answers the question of how the presence of the nerve
makes an organ not entirely plant-like: the nerve allows a psychic sensation
of hunger to be produced, thus involving an organ into animalian sense
perception. This is an important point. The tissues of an organ can be
plant-like in nature, but when put into combination with animal-like
organs, the organ is regarded as more animalian just by virtue of the whole
to which it belongs. The combination of parts has an impact on the nature
of the parts themselves.
This passage also provides an answer to the first question. Only one
small nerve is sufficient, because the nerves in these organs only need to
register a single kind of phenomenon. Once the brain is informed of the
lack of nutriment in the form of appetite, appropriate signals can be sent
by means of other sensory and motor nerves. It is also worth noting that
such an arrangement keeps the two physiological systems quite distinct:
the nerve system is only informed of the state that the nutritive system is
in; and while the former can make decisions about supplying or withdraw-
ing food, it cannot exercise any direct control on the latter.
So far, my discussion concerned the instrumental parts, especially the
stomach. Can the same explanation be used for the other two governing
parts that have nerves inserted in them? Galen himself notes, insofar as the
liver is the seat of the nutritive soul, it ought not to require a nerve,
but
then goes on to explain that the three seats of the souls need to heed each
other in the passage cited at the beginning of this chapter. He calls this a
philosophical explanation. However, for the sake of making it clear to
everyone, it is sufficient to say that the nerve is present in order that the
liver is not entirely insensible.
In the explanation obvious to everyone, the liver does not differ from a
stomach, insofar as its nerve renders it sensitive. Its special role, then, is
primarily to be explained philosophically. Arguably, the liver is distin-
guished from other internal organs by being the central part in which the
desire for bodily pleasure (arising from the vegetative soul) is located.
Notably, the stomach only begins to request food as a response to the
drawing sensation that comes when veins are emptied of nourishment.
UP . (., – Helmreich¼.–K).
Aff. Dig. .– De Boer (.K).
. Internal Perception and External Sense Perception