PLATO ON FALSE PAINS AND MODERN COGNITIVE SCIENCE
George Couvalis and Mathew Usher
INTRODUCTION
A common sense assumption about pains (and pleasures) is that they are mere
sensations with a specific sensational character. Terms like ‘pain’ (‘pleasure’) are
sometimes used metaphorically, but insofar as those terms are used literally, they
designate items that have a common sensory component that is shared by all pains (all
pleasures). Pains (and pleasures) may be contingently connected with other types of
sensation or with beliefs. However, the defining character of pains (pleasures) is due
to their specific sensational component. What makes pains painful (and pleasures
pleasant) is this sensational component that all pains (all pleasures) have in common.
Further, the badness of pains (and the goodness of pleasures) for the experiencing
subject is an intrinsic property of their specific sensational character. Pains and
pleasures differ in quantitative ways, for instance in their intensity or their duration,
but they do not differ intrinsically in any other interesting respect. In Plato’s Philebus,
Protarchus, a well meaning hedonist, defends this kind of view.1 In various places,
Protarchus makes it clear that he considers pleasure to be a phenomenon that comes
from different sources, but is always qualitatively identical (eg 12d-13c, 38a). On his
account, when we get pleasure from watching a comedy by Aristophanes, our
pleasure consists only of pleasant sensations caused by the comedy. If there is any
thought component involved in our pleasure, it is completely separable from the
sensations (the thought being the cause or the effect of the sensations). Regardless of
what we think (true or false) about the comedy, such as that it reflects important
aspects of real life, our pleasure seems to involve no possible misconceptions.
Further, any other sensations caused by the comedy, such as the sensations induced by
our jaws moving when we laugh, are only causally connected with the sensations of
pleasure.
In the Philebus, Plato puts into the mouth of Socrates the startling claim that
pleasures and pains can be false. Plato means that pleasures and pains can be false in
various ways, and some of his claims may be wrongheaded. 2 For instance, he
sometimes seems to defend the bizarre thesis that false pleasures do not exist. We will
focus on the claim that pleasures and pains can be false because they essentially
involve judgements or beliefs. We take Plato to be saying that what makes pains
painful and pleasures pleasant is that they essentially involve propositional attitudes
with an intentional content which is about the external world and which is capable of
being true or false. We will argue that Plato is right in this claim even though some of
his other claims may be false. Plato wants to defend it in order to conclude that false
pleasures are not really good. We will not consider the merits of this conclusion here.
PLATO'S ACCOUNT
1
We have followed the normal convention of referring to passages in Plato which is to use the
Stephanus numbers that are commonly used in scholarly references to the work of Plato. These
numbers and letters indicate the corresponding section on the relevant volumes of the Greek text, in
this case the Philebus except where stated.
2
Frede, D., Disintegration and Restoration : Pleasure and Pain in Plato’s Philebus., in Kraut, R., ed.
Cambridge Companion to Plato, Cambridge, Cambridge University Press, 1992, p. 443 At least four
types of falsity are considered by Plato, (1) Pleasures and pains as propositional attitudes, (2) Falsity of
overrated pleasures and pains, (3) Falsity in the identification of pleasure with freedom from pain, (4)
Falsity of pleasures intrinsically mixed with pain.
1
Plato’s background justifications
Plato partly justifies his view by means of contentious metaphysical claims about the
limited (peiron) and the unlimited (apeiron), and about whether pleasures and pains
really have being or substance (ousia). These claims are intended to connect a
problematic metaphysics with his biological theory of the function of pain and
pleasure. We will not be discussing his metaphysics in detail. However, we will be
working within his metaphysical framework in some crucial respects. First, Plato is
trying to come up with a definition of pleasure and pain as they really are. He wants to
do this in part so that he can grasp what makes pains painful and pleasures pleasant.
This is not, as he understands it, merely a conceptual task. It is a task in which we are
engaged in grasping the real nature of items in the world. (By analogy, think of
investigating the real nature of water and not merely its nominal essence in order to
understand why it is a liquid at room temperature.) Like Plato, we are not merely
doing conceptual analysis but trying to discover something about the nature of pain.
A second, related, way in which we will be working within Plato's metaphysical
framework is that like him, we think that understanding the physiology of pain is
crucial to understanding the nature of pain. Modern commentators avoid detailed
discussion of physiology, perhaps because they think he made a conceptual error in
bringing a scientific model into a central part of his philosophical argument.3
However, some modern authors have argued that a physiological conceptualisation is
necessary for understanding the ontology of pain.4 In the last half century,
essentialism has revived in the philosophy of language, the philosophy of mind and
the philosophy of science. What were once thought to be Plato's conceptual
confusions might now be thought to be deep insights. In any case, Plato's line of
argument in the dialogue make it clear that Plato thought that physiology would
provide one of the important supports for his account. We will not be discussing
Plato's physiology in detail in what follows, for although it may well have been
advanced for its time, it has been replaced by more advanced work. Instead, we will
focus on vindicating Plato's argument with some recent psychological and
neurophysiological research on pain.
Throughout the dialogue, Plato exploits the fact that pain and pleasure words in
Greek (as in English) can be used to designate states which clearly involve complex
emotions and belief-like states. He uses various root words to cover pleasure and pain
which can be used to designate what are called mental pleasure and pain as well as
what seem to be mere sensations. One root word he uses for pain is algos, which is a
rather broad word covering all kinds of unpleasant states. Another is lipi, which
covers both mental and what is commonly thought to be bodily distress. He also uses
three root words for pleasure: one word, hedone, means delight or enjoyment; hairein
means to rejoice; and terpsis means gladness or enjoyment. It might be thought that
Plato merely exploits a metaphorical connection between some emotional states and
3
For non-physiologically based discussions of false pleasures of the propositional type see, Williams,
B.A.O. Pleasure and Belief Proceedings of the Aristotelian Society, Supplementary Volume (XXXIII)
1959 also reprinted in Hampshire, S., ed. Philosophy of Mind, London, Harper & Row, 1966, pp. 22542. Penner T. M., False Anticipatory Pleasures. Phronesis, 5, 1970, pp. 166-178. Frede, D.,
Rumplestilskins Pleasures : True and False Pleasures in Plato’s Philebus Phronesis, 30, 1985, pp. 151180
4
A good example is Grahek, N., Feeling Pain and Being in Pain, Hanse Institute for Advanced Study,
1, Oldenburg, University of Oldenburg, 2001.
2
pains (pleasures). However, Mary Hesse and others have pointed out that what might
be thought to be merely metaphorical connections between items often turn out to be
deep similarities between them. Such similarities can be indicated by the appearance
of various items, as well as by similarities in their effects. Intellectual progress often
consists in coming to grasp that what were thought to be merely analogical or
metaphorical connections are really cases of deep similarity.5 We will see that
although physical pains and unpleasant emotional states are importantly different,
they nevertheless have deep and not merely shallow similarities.
Plato’s arguments
Plato initially claims that just because a group of items come under the rubric
‘pleasure’ (or the rubric ‘pain’) does not necessarily mean that they are alike in their
goodness (badness). They may be opposed to one another just as the colours black
and white can be said to be opposed to one another while still being colours. More
importantly, they are not alike essentially because of a common sensational content
(12d-13c). There may be a sensational component shared by pains, but it is not what
unifies pains as painful (pleasures as pleasant). Further, he hints that once we realise
what unifies them is that they are propositional attitudes of a certain kind, we realise
that they can be not merely alike but importantly different because some can be true
while others are false.
To stun Protarchus, Socrates argues that memory is crucially involved in any
enduring pleasures, as pleasures could not survive from one moment to the next
without a background memory (21b-c).6 Plato hints that the process involved must be
in some sense intelligent as it involves bringing together a memory of past sensational
contents with present sensational contents and treating them as one continuous item.
Further, Socrates argues that to enjoy ourselves we must be able to judge that we are
enjoying ourselves, and this clearly involves an intelligent process. These arguments
don’t establish that pleasures (and pains) are propositional attitudes, though they seem
to show that some sort of cognition is essentially involved in the pleasantness of
pleasures (and the painfulness of pains). To understand why, consider that when we
perceive items in the external world, their existence is not dependent on our
perceptions. In their case, the intelligent use of memory is only necessary in order to
perceive them. However, when we perceive pains as painful (and pleasures as
pleasant), the mode of our perception of them seems to be essential to their
painfulness (pleasantness). This means that a cognitive state involving background
memory seems to be not only necessary for perceiving them, but an essential part of
them.
At 35a-e Socrates follows up his earlier arguments by putting the claim that
pleasures (and pains) must be understood to be intentional states directed towards
objects of desire (or aversion). As he puts this point, they are states of the soul and not
of the body. In his argument, he treats as types of pain thirst, hunger and other states
that he takes to necessarily involve desire. His underlying claim is that for states to be
pleasant or painful, there must be a perception that something makes up for a lack in
us (and/or a perception that something is lacking in us). Such perceptions cannot be
5
A famous example is the apparently metaphorical description of light as a wave. See Hesse, M.,
Models and Analogies in Science, Notre Dame, Indiana, University of Notre Dame Press, 1966 ; Lamb,
D., Discovery, Creativity and Problem-Solving, Aldershot, Avebury, 1991
6
See also Philebus, 33c, 34a, 35a-d, 36b, for more on the role of memory.
3
merely given in some pure sensory content. For us to be pleased or pained we must
be aware of a lack in us and be aware that some object is the opposite of that lack in
the sense that we must perceive it as the remedy for that lack. We are in touch with
the objects in the world which we know will make up for a lack in us through
memory. In modern terms, there is a specific kind of ‘this is good for me’
intentionality involved in pleasure (and ‘this is bad for me’ intentionality involved in
pain).
For Plato, infant thirst has a minimal intentional character for it is consciousness of a
lack in the body and a desire for filling which is not intentionally directed towards a
specific external object. It differs from the thirst of experienced individuals which has
a more full blooded intentional character; for experienced thirst is a desire for things
outside the body in which memories of what has previously been experienced to fill it
are crucially involved. Such intentional states involve necessarily memories of past
events and beliefs that certain things are beneficial or dangerous.
In the Theaetetus (156b), Plato had put pleasures and pains in the same category as
hearings, seeings, fears and other items. He called them perceptions (aistheses). To
treat them in this way is already to treat them as judgements which are more than
sensations. In the Philebus, which is written later, he treats some pleasures and pains
as perceptions. For instance, he often treats pains as the perception of a deficit, and
pleasures as the perception of the restoration of a deficit (31d-32b). However, Plato
makes clear that he thinks a pleasurable perception is (typically) not only the
perception of restoration, but a perception that a particular external object is restoring
us. Further, in the Philebus, it is not essential to pleasures or pains that they be
perceptions, for there are anticipatory pleasures in which the body is not involved, but
only the soul (32c-33c, 35c-e). Plato treats such anticipatory pleasures, which
obviously involve sophisticated cognitive states, as paradigmatic examples in order to
argue that all pleasures and pains have a sophisticated cognitive component that is
essential to them.
At 36c Socrates directly introduces the idea the pleasures and pains can be true or
false. Protarchus indicates that he cannot see how this is possible. Socrates draws an
analogy with fears expectations and judgements, claiming that they can all be true or
false. (Fears and expectations seem to necessarily involve anticipatory judgements).
However, Protarchus denies that this is true except in the case of judgements. Socrates
gets Protarchus to say that there is something a pleasure is about at 37a. Socrates then
asks why pleasure 'admits only truth' whereas judgements admit of truth or falsity?
What he is getting at seems to be that it is puzzling that when we are pleased we can
be in no doubt that we are pleased, whereas when we judge, for instance, that
something is round, we can be mistaken. He follows his question up later with the
question: how is it that pleasures can be bad? He wants to say that we can only answer
these questions if we treat pleasures as like perceptions in which it is as if there were a
picture in the soul but also a judgement. I take it he means that if we understand
pleasures in this way, we could be in no doubt that there is a judgement and we can
understand how the judgement could be bad - the badness would be a kind of falsity.
He also says that the proper way to understand the nature of fear and anger is similar.
We will not discuss the later parts of the dialogue. It is important to note that at
many points we are shown through Protarchus' behaviour that while Plato can make
4
his position plausible, he is unable to provide a very strong case for it. Protarchus
often agrees with Socrates, but then withdraws his agreement or shows his discomfort
with it. This is not because Protarchus is shown to be debauched like Philebus. On the
contrary, he is portrayed as a genuine seeker after truth who can vaguely grasp that
Socrates' line of argument is subject to a general objection. The general objection is
that Socrates is constantly mixing up items that are contingently connected with
pleasure (pain) with pleasure (pain). Had Plato not been so biased in favour of his
own view, he might have shown this more clearly in the dialogue. For instance, in
response to Socrates' view about anticipatory pleasures, he might have had Protarchus
attempt to distinguish the pleasures from the sophisticated judgements which produce
them. In following this line of thought, Protarchus would have consistently denied
that pleasures and pains have an intentional object, something he foolishly admits in
the dialogue. If he were to argue in this way, Protarchus would not be producing an ad
hoc hypothesis to defend his view, for when we are pained, we always seem to be in
the grip of very obvious sensations which have a specific character. These might be
thought to be constitutive of the painfulness of pain. Thus, it is not unreasonable for
Protarchus to think that it is solely sensational content that makes pain unpleasant and
that judgement is only contingently connected with the unpleasantness of pain.
Protarchus might have become a thorough Benthamite by following this line of
argument. He might have claimed that the pleasure the axe murderer gets in killing is
in itself good, even if the axe murderer's actions are bad all things considered.
We have argued that Plato's argument for his view is inadequate. Modern defenders
of his view have relied on conceptual analysis or intuition. Arguments from
conceptual analysis or intuition are subject to the general objection that pains might
be quite different from the ways in which we conceive them. After all, science has
shown that the folk concepts of a vacuum and of heat are quite inadequate.
Remember, however, that we have emphasised that Plato relies in important part on
an antiquated biology and psychology of pain. This makes us realise that an up to date
biology and psychology of pain might bear out his view. Three kinds of evidence
might be discovered: A) Evidence that there are two biological systems which can be
dissociated, one producing the sensory component of pain and one producing the
propositional attitude component which makes pain unpleasant. (We are speaking
here of what cognitive scientists call a double dissociation.) B) Evidence that the
propositional attitude component of pain is crucial to making non-central cases of
pain unpleasant. C) Evidence that in typical cases of pain, the sensational component
is not essential.
As we will see, modern research has brought to light evidence of kinds A and B, but
has rendered Plato's attempted unification of unpleasant states solely via their
propositional attitude content problematic.7
MODERN RESEARCH
Researchers have turned up three types of cases that are particularly relevant to
Plato's account. All three types of cases usually result from lesion damage or surgery
7
The reader should note that there is another line of argument Plato could take, which is to argue by
using modern research that the sensational content itself is representational. As far as we can tell, this is
true, but the representational content has nothing to do with the painfulness of pain. On the contrary, it
is emotionally inert. This means that while pointing out that the sensory content of pain is
representational would undermine Protarchus, it would not support Plato.
5
to very specific parts of the brain, although they can be the result of other conditions.
People who have the conditions we will describe can be otherwise normal and
certainly quite rational.
In cases of type 1, which are called cases of 'pain asymbolia', people report that they
feel pain and can describe it in considerable detail while saying that it does not bother
them. Such people commonly laugh in surprise at the fact that they are in pain and
sometimes even describe the pain as 'agonising', despite the fact that the pain does not
bother them.
In type 2 cases, people are not bothered by what would normally be dull chronic pains
unless they are brought to their attention and they focus on them. They then dislike
them. When their attention goes elsewhere, they are not bothered by pain at all.
In type 3 cases, patients report unpleasantness, but, apart from locating it only in the
vaguest manner, cannot specify its sensory characteristics. In the best described case,
the patient could not characterise the feeling he had in terms of the well known
characteristics of pains. For instance, he did not have a feeling that he would
characterise as burning, prickling, cold or hot. He could not describe the feeling as
slight pain or intense pain. He had a feeling somewhere between fingertips and
shoulder that he could only characterise as unpleasant and wanted to avoid. Although
the feeling was actually produced by the researchers by stimulating pain fibres, the
subject did not perceive the unpleasantness as pain. 8
What explains such bizarre behaviour in otherwise largely normal people? The
repeated results of various studies, including brain scans, have led researchers to
consider the pain system to be two interactive yet distinct subsystems. 9 We have
what is called a ‘sensory discriminative’ system and this gives us the location,
intensity, duration, and nature (stabbing, burning, prickling) component of the
stimulus.10 We also have the affective motivational system that consists of several
structures and it is the activity of these structures that make pain experiences
phenomenologically unpleasant.11 The activities of the two systems can be
dissociated. When we realise this, we can produce a simple explanation of why people
who have pain asymbolia laugh in surprise at the fact that they can have intense pain
that does not bother them. The explanation is that the folk concept of pain mistakenly
includes in it the belief that the characteristic sensations of pain can only occur if
unpleasant pain affect occurs.
8
Ploner, M., Freund, H.-J., and Schnitzler, A., Pain affect without pain sensation in a patient with a
postcentral lesion Pain, 81,1999, pp. 211- 214. Also, Fentanyl causes painfulness yet severely inhibits
our discriminatory sensitivity. Sufferers of Parkinson’s disease and Huntington’s chorea often report
that they feel pains but are unable to localise them. See Hardcastle, V.G., The Myth of Pain, Cambridge
Massachusetts, MIT Press, 1999, p 104
9
Aydede, M., An Analysis of Pleasure Vis-aVis Pain, Philosophy and Phenomenological Research, 61,
3, Nov 2000, p. 544-545
10
ibid, p. 545 This system is served by the ventrobasal thalamus at which noxious stimuli arrive
through the spinothalamic and neospinothalamic projection systems and go directly to the
somatosensory cortex.
11
ibid, p. 549
6
The Sensory and Affective Systems
The sensory system, gives discriminative information about the location, intensity,
duration, and nature of noxious stimuli. It is served by networks of nerve fibres found
in most of our tissue. Nerve endings in our tissues called receptors, come in many
different types and their receptive fields often overlap.12 Damage at any point in our
tissue will activate at least two or more of these networks and send nerve impulses
along sensory nerve fibres that run into the spinal cord.13 The sensory pain fibres
come in two types A-delta (Ad) and C fibres. Nerve impulses produced by injury are
conducted rapidly to the central nervous system by Ad fibres which are very sensitive
to the specific injurious agent’s pressure, thermal, or chemical characteristics. C fibres
are also sensitive to characteristics of injurious stimuli but are much slower in
transmission than Ad fibres. 14 The C fibres have an important function based on their
release of chemicals into nerve endings. 15 This chemical signalling system is the basis
for the increased excitability, sensitivity changes and long lasting effects like
tenderness of the area, that follow injury.16 The firing of Ad fibres is an important
causal agent in causing immediate acute pain. The firing of C fibres is important in
causing chronic pain.17
Indifference to these noxious signals from nerve fibres can occur as a result of
disease (congenital, and psychosis), but also in quite normal and healthy people
whose attention is engaged elsewhere, as in sports people and soldiers.18 It is
important to note here that indifference to noxious stimuli is not the same as pain
asymbolia. In these cases people are indifferent to noxious stimuli that normally, but
are not in this case, accompanied by unpleasant feelings, that is, they are not
conscious of injury or pain, whereas in asymbolia cases people are indifferent to pain
which is present at the forefront of consciousness.19
The limbic system is a collection of structures that surround the thalamus on each
side of the brain and includes parts called the hypothalamus, hippocampus, amygdala,
septum and cingulum. 20 It is often referred to by researchers as the, ‘emotional HQ’
of the mind.21 Surrounding these is the cerebral cortex (which is of course larger and
more developed in more highly cognitive animals).22 The limbic system interacts with
sections of the frontal cortex (cognitive HQ) that are accordingly, functionally
12
Melzack, R., and Wall, P., The Challenge of Pain, London, Penguin, Third edition, 1988, pp. 82-84
It is postulated that a gating mechanism exists in the spinal cord that plays a significant role in
modulating the impulses from nerves. We will not be discussing the gate theory here. See Melzack, R.,
and Wall, P., 1988, opcit Chapter 9, pp. 165- 193.
14
ibid pp. 86-88, 101. Fibers do not respond to all stimuli, some are very sensitive to specific stimuli
like hair movement, skin or tissue indentation, crushing, stretching, warming, cooling, or chemicals.
15
ibid pp. 99-100
16
ibid, pp.99-100
17
Chronic pain is the term for a number of different pathological conditions including ; pain in the
absence of any stimulus, pains that last longer than what they should under normal conditions and
sometimes never cease, pain in response to what should be non-painful stimuli, pains of greater
intensity than normal, pain spreading to uninjured tissue, pains for which the cause may or may not be
known but treatment is ineffective. ibid pp. 288-289
18
Correlation between the firing of nerves and the perception of pain is very weak, see Hardcastle,
1999, opcit p. 106, 122. Melzack, R., and Wall, P., 1988, opcit Chapter 1, pp. 3-15
19
Grahek, N., 2001, opcit pp. 105-106
20
Melzack, R., and Wall, P., 1988, opcit p. 124
21
Hardcastle, V, G., 1999, opcit p. 116
22
Melzack, R., and Wall, P., 1988, opcit p. 124
13
7
designated as parts of the limbic system.23 Evidence indicates that the limbic
structures are particularly important as the basis for the aversive drive and affect
(painfulness) of pain and the attraction / attention (pleasantness) of our pleasure as
well as other kinds of behaviour.24 The highest concentration of opiate receptors in the
brain is in the limbic system.25 The role of the limbic structures becomes more
complex and subtle when we consider that they are strongly interconnected with the
somatosensory cortex and cognitive processing areas like the frontal cortex.26
Lobotomies and surgical section of limbic structures results in loss of painfulness in
pain sensations, particularly in chronic pain. This procedure is performed on people
whose long term, chronic and intractable pain, fails to respond to all other treatment
methods. Some of them involve the removal of certain parts of the brain located in the
frontal lobes, or the whole lobes themselves often severing the projections between
the thalamus, hypothlamus and cingulate cortex.27 These people (type 2 cases) no
longer feel the painfulness of, or aversion to chronic pain. Like complete asymbolia
patients (type 1 cases) they perceive pain, it just doesn’t bother them unless they focus
on it. They still feel sensory / discriminative sensations of pain, (location, intensity,
type), particularly in the case of new or different acute pains, identify them as pains,
but are only briefly or not at all upset by them and show only transient pain behaviour
(wincing, moaning, complaining) if any. These sections and lobotomies do not
interfere so much with the perception of pain, or normal immediate reactions to pain,
particularly new pains, but reduce the long lasting, persistent emotional substrate of
chronic pains.28 The patients lose their fear of pain. 29
A similar dissociation effect is reported by people on morphine for pain, and people
who undergo hypnosis and are told that their pains will not hurt anymore.30 In
particular evidence indicates that the anterior cingulate cortex, an area primarily
involved with emotion and attention and strongly interconnected with the limbic
system, needs to be active for someone to feel aversion to a painful stimulus.31 PET
scans done on patients under hypnotic suggestion that their pains would not hurt,
showed that activity in the cingulate cortex decreased while in the somatosensory
cortex (primarily involved in the discriminative processing) activity remained
unchanged.32 Cingulotomies, (removal of the cingulum) do not have the global
23
ibid p. 134
ibid p. 132-137, “The amygdala seems to provide an ‘affective bias’ as a result of matching incoming
information against past experience so that animals and people can respond adaptively to familiar or
unfamiliar stimuli. … After ablation of the amygdala, monkeys unhesitatingly ingest hot, sharp or
otherwise injurious objects that normally, on the basis of past experience, elicit caution or avoidance.”
p. 135.
25
Aydede, M., 2000, opcit p. 555. Several descending control systems use endorphins and enkephalins
the bodies own opiates, see Melzack, R., Wall, P., opcit p. 137-144
26
Melzack, R. and Wall, P., opcit pp. 134-135
27
Hardcastle, V, G., 1999, opcit p. 117
28
Grahek, N., 2001, opcit p. 121.
29
Freeman, W., and Watts, J.W., Psychosurgery in the Treatment of Mental Disorders and Intractable
Pain, Oxford, Blackwell, 1950, p. 353
30
See Damasio, A. R., The Feeling of What Happens : Body and Emotion in the Making of
Consciousness, New York, Harcourt Brace, 1999, p. 75. Hardcastle, V.G., 1999, opcit, p. 104. Carter,
R., consultant ed, Christopher, F., Mapping the Mind, London, Weidenfeld and Nicolson, 1998, p. 114
31
Carter, R., 1998, opcit p. 114
32
Rainville, P., Duncan, G. H., Price, D. D., Carrier, and Bushnell, M.C., Pain Affect Encoded in
Human Anterior Cingulate But Not Somatosensory Cortex, Science, 277, 1997, pp. 968-971
24
8
personality effects of lobotomies, however patients do show attentional and executive
deficits.33 Evidence suggests that damage to the anterior cingulate is typically
involved in cases where what seems to be lacking is some kind of active background
memory.34 The anterior cingulate, also seems to coordinate perceptions of bodily
threat with frontal areas in the cortex involved in plans and response priorities.35
In the case of pain asymbolia, (type 1 cases) the sensory character of pain has been
totally dissociated from its normal affective character apparently because of damage
in the rough area called the posterior insula which either cuts the connection between
somatosensory information and the limbic system or destroys the ability to perceive a
variety of kinds of information as threatening. 36What seems to be lacking in both type
1 & 2 cases is high level cognitive evaluations of painful stimuli which have to do
with the long term implications of bodily damage. Suffering anxiety, dread or fear
concerning pain is essential to the painfulness of chronic pain.
We have mentioned type 3 cases. Consider the only well studied example of a type 3
case in the literature. The patient's state was produced by stimulating C fibres.
However, what he experienced was not pain, even though it was unpleasant. The
reason is that the patient was not aware of the sensory reports normally produced by C
fibres, which would give a unifying painful character to his experience. As Nikola
Grahek has correctly said, this patient suffers from painfulness without pain.37 It is
important to stress, however, that he does not experience it specifically as painfulness,
but merely as an unpleasant state which cannot be characterised in any detail. By
contrast, in the type 1 and 2 cases we have described above, the patients are not in
doubt that they are in pain because the sensory unity in their experience is intact. They
are feeling pain which they can characterise either as burning or pricking etc.
However, what they experience lacks painfulness. It is, to their amazement, in no way
unpleasant. We see from all this that the sensory character which unifies the
experience of pain has nothing to do with painfulness. These facts seem to fit Plato's
account beautifully and seem to refute Protarchus's account.
Cognitive Content
It has long been argued that memories, present perceptions and associations, cultural
factors, beliefs, goals, fears, and expectations influence pain perception. Modern
research on the brain shows that areas of the brain functionally responsible for
emotion and cognition have a significant role in our normal, paradigmatic pain
experiences. Paradigmatic pains (like cutting yourself with a knife) are complex
constructions with many dimensions that involve our current experience of sensory
discriminative information combined with past understandings of similar experiences
and our beliefs about the world.38 Even before noxious stimuli arrive at brain areas
involved in pain experience, they have been modulated by higher brain mechanisms.
Contentful mental states like memories, and propositional attitudes like fears, goals
33
Grahek, N., 2001, opcit p. 129
ibid pp. 127-129
35
Price, D. D., Psychological and Neural Mechanisms of the Affective Dimension of Pain, Science,
288, 2000, p. 1771
36
Grahek, N., 2001, opcit p. 54. See also Price, D.D., 2000, opcit p. 1771
37
ibid p. 8
38
Hardcastle, V.G., 1999, opcit pp. 118-119
34
9
and expectations, singularly and in combination, play the essential role in
painfulness.39
Consider these two experiments that demonstrate that propositional attitudes
(expectations and fears) make the character of our sensory experience. One
experiment was done on patients undergoing a procedure that involved inflating a
balloon in their bowels.40 The inflation of the balloon is reported as painful by
patients. In this experiment patients who had just had the balloon inflated and then
deflated were told that the balloon was being inflated again, but in fact it was not. The
patients reported that they could feel the (rectal) pain from the balloon being inflated
even thought it was not. A PET scan was done during this experiment, and the reports
of pain from the (false) inflation of the balloon showed activations in the prefrontal
cortex. 41
Another simple experiment demonstrates the involvement of expectations in pleasant
and painful affect.42 Participants were asked to agree to experience either a painful,
pleasant or neutral sensation. All participants placed their fingers in a machine that
(unbeknownst to them) simply had a vibrating emery board. Those participants that
signed on for the painful (but harmless) sensation were expecting a painful sensation,
and reported that indeed the sensation was painful, while those who signed on for the
pleasurable sensation expected pleasure, and reported a pleasurable sensation. Those
who signed on for the neutral sensation agreed that the sensations they felt were
neither pleasant nor painful. The experiment provides good evidence that the
awfulness (affective motivational aspect) of pain is not caused by the sensation or
noxious stimulus but is already part of how we perceive the stimulus or sensation.
Beliefs about the consequences, the “meaning” of your injury, and thoughts about
how your body has perhaps been fatally damaged make pain sensations significant.
The opposite can also occur, where beliefs and expectations of “good” things can
change what we feel. The classic example of this is the placebo. Research shows that
placebos relieve pain at half the rate of the supposed drug, whatever the supposed
strength of the drug is.43 Beliefs informed by memories of past experiences can form
sophisticated schemas; that is, patterns of concepts, response patterns and associations
drawing from memories, present experiences and expectations.44 Belief structures
about injury, its consequences, and lethalness can be ingrained and conditioned.45
Fear and anxiety, expectations and memories connected with our sensory perception
makes the aversive affective dimension, the unpleasantness, a contentful and
meaningful state that engages our attention. It makes good evolutionary sense that our
39
ibid pp. 170-171
Silverman, D. H. S., Munakata, J.A., Ennes, H., Mandelkern, A., Hoh, C.K., Mayer, E.A., Regional
Cerebral Activity in Normal and Pathological Perception of Visceral Pain, Gastroenterology, 12, 1997,
pp. 64-72
41
ibid, pp. 65-68
42
Anderson, D., and Pennebaker, J., Pain and pleasure. Alternative interpretations of the identical
stimulations. European Journal of Social Psychology 10, 1980, pp. 207-210
43
Hardcastle, V.G., 1999 opcit p. 106
44
Melzack, R., and Wall, P., 1988, opcit p. 136. Hardcastle, V.G., 1999, opcit p. 119., Study and
schema theory by Chapman, R.C., and Nakamura, Y., Hypnotic Analgesia : A Constructivist
Framework, The International Journal of Clinical and Experimental Hypnosis, XLVI, 1, 1998, pp. 626
45
Hardcastle, V. G. 1999 opcit p. 114
40
10
beliefs about the nature of our bodies and the dangers posed by injury are involved in
the affective aspects of pain.
Childhood Pain
There is evidence that the suffering of pain, remembered or not, effects later
experiences of pain. 46 This would seem to occur because of developments in both the
sensory discriminative, and the affective pain systems of the brain. It is well
documented that injurious stimuli increase the size of the somatic fields for neurones
sensitive to pain and aids in maintaining neural connections that might otherwise have
atrophied away.47 Hence pain behaviour and experience can be influenced by earlier
sensory inputs as a result of the traces they have etched into neural connections.48 It
has been plausibly postulated that chronic pain and hyper- sensitivity may be the
result of early acute painful experiences.49 A study showed that neonatal circumcision
effected pain response with higher behavioral pain scores for months after the
operation. 50
Given the immaturity of infant and child brains we might expect that their pain
experiences are significantly different to those of adults. Not only might we expect
their sensory system to be less developed and attuned, but also the affective
motivational system, descending control systems and beliefs about the world will be
immature compared to those of adults and older children. 51 A handful of studies done
on infant and child pain do suggest that infant and child pain experiences are different
to those of adults. Studies have shown that infants have simple, diffuse, and less
modulated reactions (poor localisation and reflex withdrawal) to painful stimuli than
adults and older children.52 More focussed responses (defensive reflexive movements,
greater localisation) to painful stimuli do not emerge until after 12 months. 53 It has
been observed that pain thresholds decrease with age, while the ability to localise pain
increases.54 But while the sensory component might take some time to mature, infants
do nevertheless exhibit enhanced acute pain responses and the typical stress responses
to tissue damage like sweating, increased heart and respiratory rates, and hormone
level changes.55 Furthermore infants cry when given inoculations, but can be soothed
by comforting or the administration of analgesics.56 This would suggest that infants
are experiencing something painful despite the immaturity of their sensory system.
As children grow and experience more they will attach meanings and emotions to
their life experiences and begin to have more sophisticated hopes and fears.
Researchers have shown that anticipatory fear is evident in infants as young as 6
46
ibid p. 199
ibid p. 199
48
Melzack, R., and Wall, P., opcit p. 124
49
Hardcastle, V. G., 1999, opcit p. 199
50
Taddio, A., Goldbach, M., Ipp, M., Stevens, B., and Koren, G., Effect of neonatal circumcision on
pain responses during vaccination in boys, 1995, Lancet, 345, pp. 291-299
51
Hardcastle V.G., 1999, opcit pp. 194 –200. Neurophysioloical evidence supports this.
Thalamocortical fibres do not reach the cortex until 26 weeks gestation. The neural activity of
somatosensory cortex, prefrontal cortex and anterior cingulate increases substantially from birth to
eighteen months, but does not reach mature form until after a year.
52
ibid pp. 194, 197
53
ibid p. 194
54
ibid p. 194.
55
ibid p. 197
56
ibid p. 197
47
11
months and that as they grow older the pain reaction in young infants and children is
replaced by anger.57 This suggests that beliefs and attitudes about the causes,
desirability, and understanding of pain are developing and changing as children grow.
Also as we mature we develop skills for coping with pain and make use of these
skills. Infants and very young children, by contrast lack the coping skills that adults
and older children have, and may well feel more painfulness than an adult would in
some circumstances.58 Children’s pain behaviour may not look like pain behaviour to
an adult. Apparently children with chronic pain report that they are in pain, but show
no typical pain behaviour, while repeated acute pain in children often resembles
chronic pain in adults.59
PLATO'S ACCOUNT AND MODERN RESEARCH
What can we conclude from all this concerning Plato's account? Plato's view that the
painfulness of pain does not consist of some sensory character all pains have seems to
be borne out. The characteristic sensations we typically get when we are in pain can
be dissociated from the painfulness of pain, and vice versa. Further, Plato seems to be
correct in thinking that it is an integral part of the painfulness of pain that we have
memories and/or other cognitively sophisticated states which are in part to be
understood to be propositional attitudes capable of being true or false. We have seen
that this is particularly clear in the case of chronic pains. Finally, Plato seems to be
importantly correct in thinking that infant pain is importantly different from the pain
of adults or older children.
Protarchus might still try to respond to Plato's central claim by arguing that although
we have shown that much of the sensational content of pain is irrelevant to its
affective character, we have not shown that there is no aversive felt content left which
is purely sensational. To reply to this response, let us consider the above mentioned
case of a patient who experienced an ill localised pain which he could characterise in
no other way but by its unpleasantness. The puzzled patient, who is a normal rational
person, could not perceive his pain as either intense or not intense, either burning or
pinprick like, or in any other way researchers suggested. Discussion with the patient
and brain scans showed that this patient is not experiencing any of the normal
somatosensory characteristics of pain, but found what was happening to him intensely
unpleasant and wanted to avoid it.60 To say that this patient was having a mysterious
kind of pain sensation seems to us merely an ad hoc manoeuvre. The simplest
explanation is that the patient merely is aware of his propositional attitude that he
would like to escape from an unspecific causal agent. The experimenters and the
subject are inclined to call it a feeling because the subject is aware of his negative
propositional attitude to a causal agent acting in a very ill localised area, not because
his experience has any other painful sensory character. Of course, it would be possible
for Protarchus to say that the subject was having a special kind of aversive sensation
which cannot be characterised any further. However, for him to respond in this way in
the absence of any other sensory characterisation of the experience would be for him
to indulge in an untestable ad hoc manoeuvre.
57
ibid p. 194
ibid p. 195
59
ibid pp. 194- 195
60
Grahek, N., 2001, opcit. pp. 100-103
58
12
We should note, however, that some important parts of Plato's account are not
correct. The reader will remember that Plato proceeds by talking as if thirst, hunger
and other unpleasant states are pains in essentially the same way as paradigmatic
cases of pain. Research which has been done on various unpleasant states shows that
Plato may be partly correct. Part of what unites various unpleasant states is emotional
states. The same parts of the limbic system are activated in many emotional pains as
in physical pains. This is probably why they are called emotional 'pains' in various
languages.61 But matters are not as simple as this, for while there are two dissociable
systems in the brain, they normally work together as parallel distributed systems
which strongly interact. We cannot explain the workings of parallel distributed
systems here, or discuss the detailed workings of the pain system. However, it is
sufficient to point out that the merger of the activity of the two pain systems in the
brain is often not like the mixture of the activity of two atoms which do their work
separately, but like the merger of two waves in a new wave, in which the two previous
waves have no separate existence. This is probably why the emotional attitudes and
the sensational contents of pain fuse in the everyday phenomenology of pain.62
A related problem with Plato's account is that the different phenomenology of
paradigmatic pains reflects something crucially different from other unpleasant states
and which has to do with the underlying physiological states that are involved. The
function of Ad and C fibres has nothing to do with lack. Ad fibres are finely tuned to
warn of potential mechanical, thermal or chemical damage and to cause rapid
reactions to the threat of such damage. C fibres have more than one function. Some
of them function to give fine grained reports of the locality of pain.63 All of this
suggests that paradigmatic pains are fundamentally different from other states that are
called pains in a looser sense. In paradigmatic pains, fine grained content is present
which warns of highly specific kinds of actual or potential harm and provides
information about the precise site in which the threatening cause is active. The
informational content is very rich in paradigmatic pains, and very different from that
in other unpleasant states. Thus while Plato is correct to stress that a crucial aspect of
typical pains is that they are propositional attitudes, he is mistaken in treating the
sensory aspect of pain as of minor interest.
George Couvalis,
Matthew Usher
E-mail Address :
george.couvalis@flinders.edu.au.
matteusone@primus.com.au
The Flinders University of South Australia.
We thank the members of the Philosophy Department of the University of Valencia,
Spain for their helpful comments, particularly Josep Corbi and Jordi Valor.
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