Qualia personal - an important lesson for anti-elitists?
Peter H.M. Brooks
before. It seems that the question has now been answered, we do not see the
world in the same way, our qualia are personal. My red may be quite a
different quale from your red.
Now that that's out of the way we can investigate the implications. I
am quite surprised by the result as I had imagined that other people's
qualia were much the same as mine - from their descriptions and reaction to
the world. I have tended to dismiss different reactions as being for other
reasons - philistinism or perversity for example. However, if people truly
do see a delicate watercolour landscape as just grey blobs; smell (and
consequently taste) a truffle omelette as similar to a mcshite hamburger and
hear Bach as similar to badly played bagpipes then it is no wonder they
can't appreciate them! There seems little point in trying to teach such
people either - as with trying to teach a pig to dance, it just wastes your
time and annoys the pig.
It must also be true that one could measure the level of acuity of all
the senses and discover the fortunate elite with the finest senses who are
best placed by their genes to be artists, chefs, musicians and perfumers.
Training then would not be wasted on those incapable of reaching such
heights of perfection.
The article follows:
In the realm of your senses
New Scientist vol 181 issue 2432 - 31 January 2004, page 40
We have all wondered whether other people see, smell and touch the
world in the same way we do. Now there are some real clues to the answer,
says Richard Hollingham
IT'S a classic philosophical conundrum: how does my perception of the
world differ from yours? Take a red rose, for example. We can probably agree
it's red rather than blue, but what exactly is "red", and do I see the same
red as you? And what about the distinctive smell - is my sense of what
constitutes a rose's scent the same as yours?
Philosophers have been wrestling with this question for centuries.
Sensory scientists, too, have long been interested in why people report such
different experiences of the same odours or flavours. Is it purely
subjective, or based on some objective difference in their sensory
experiences?
The obvious answer is that there is no way of knowing because sensory
experiences are inherently private. But biologists have recently taken a
fresh look at the question and concluded that we can know. Sensory
experiences are highly individualised. "No two people live in the same
sensory world," says Paul Breslin, a neuroscientist at the Monell Chemical
Senses Center in Philadelphia. "The world you see, the foods you taste, the
odours you smell - all are perceived in a way unique to you."
It's all down to our DNA. In the past few years geneticists have
unearthed huge numbers of genes involved in the perception of taste, smell,
touch and vision. Olfactory receptor genes, for example, account for around
3 per cent of the total - only the immune system takes up more houseroom.
And not only are sensory genes vastly abundant, they are highly variable
too. This means that individuals rarely have exactly the same set of sensory
genes. And, crucially, individual genetic repertoires are now being linked
to differences in the way people report their experiences of the world. Some
scientists even think that the set of sensors you inherit has a profound
effect on your life and personality.
If all this is too much to cope with, sit down and have a drink. It's
as good an example as any.
"I love gin and tonic," announces geneticist Dennis Drayna - he uses
his favourite tipple to explain his research. He works at the National
Institute on Deafness and Other Communication Disorders in Rockville,
Maryland, and his speciality is bitter-tasting substances. "I could even
drink the tonic without the gin," he says. "I really like the bitter taste."
But not everyone shares his predilections. Give a single concentration
of any bitter chemical, such as the quinine in tonic, to a selection of
people and they will have remarkably different responses. "Most will tell
you it's moderately bitter, some will say it's not bitter at all and a few
will yell at you for trying to poison them," Breslin says.
That much has been known for a long time. But Drayna, Breslin and
others have now started linking these subjective differences in taste
perception to the genes that code for taste receptor proteins in taste buds.
They work with perhaps the most famous bitter flavour,
phenylthiocarbamide or PTC. This chemical was discovered in the 1930s by
Arthur Fox, an industrial chemist at DuPont who was researching artificial
sweeteners. Fox discovered that some of his colleagues found the chemical
incredibly bitter while others, including himself, could not taste it at
all.
The ability to taste PTC was long thought to be a case of simple
Mendelian inheritance. People with two copies of the recessive "non-taster"
version were unable to taste PTC; others could. But this distinction has
turned out to be too simplistic. Even though the trait is broadly "bimodal"
with reasonably distinct taster and non-taster groups, there is a lot of
variation within the groups. "If the concentration is high enough [about 360
parts per million] everyone can taste it," Drayna says. Some tasters can
detect PTC at the vanishingly small concentration of 18 parts per billion.
Drayna set out to find the genetic source of this variation. He asked
267 people whose genomes had already been sequenced to take a taste test in
which they had to sort six cups of water, three containing a known
concentration of PTC and three without. He repeated the test at different
dilutions to find each person's taste threshold. Then he compared the
results with the sequence of a region on chromosome 7 previously identified
as the location of the genes that code for bitterness receptors. As a result
the team identified the PTC receptor gene and also found it came in five
different "flavours" that differed from each other by a single base pair.
These alterations were sufficient to explain the difference between the
volunteers' taste thresholds.
The PTC gene codes for only one of 23 different bitterness receptors,
which gives an idea of the possible diversity. Initial analysis of other
taste receptors hints at equally wide variance. So it looks as though your
tastes in food really are your own.
Olfaction, too, is proving to be hugely variable, though in a subtly
different way. Humans can distinguish around 10,000 different smells via 400
receptor proteins lining the nasal cavity (see Diagram). But it has long
been known that not everyone smells the same smells - and now geneticists
have shown that this could be because everyone has a different set of
receptors.
Olfactory receptor genes are distinctive and easy to spot from their
DNA sequence. So it came as a surprise when the human genome turned out to
contain about 1000 such genes. How did this tally with the 400 known
receptor proteins? It turned out that around 600 are "pseudogenes" -
sequences that look like genes and are inherited like genes but have lost
their function. For sensory scientists this was an intriguing discovery, as
pseudogenes are known to have lost their function very recently. So a team
at the Weizmann Institute in Rehovot, Israel, wondered whether some
olfactory pseudogenes were still functional in some people, and whether this
tallied with differences in what they were able to smell.
In a study published in Nature Genetics (vol 34, p 143), the team
identified 51 pseudogenes that are functional in some people. Then they took
189 ethnically diverse volunteers and examined their olfactory receptor
genes. They found that each person had a unique combination of functioning
pseudogenes, giving them an individualised repertoire of smell receptors.
However, team member Yoav Gilad is not yet prepared to associate this
genetic variability with the results of smell tests. "Although studies have
shown big differences between smelling abilities, unlike with PTC, there's
no proof that this is genetically based," he says. Although he concedes that
genetics almost certainly plays a role, "there are a lot of other
environmental and psychological factors as well". For example, when people
are given coloured water and clear water that smelt identical when sniffed
blindly, a majority say the coloured water smells stronger.
Of course, an innate revulsion to tonic water or heightened ability to
smell a rose is unlikely to have a major impact on your life. However,
differences in other senses could prove more significant.
In humans there is one sense we rely on more than others - sight. But
light perception and colour vision can differ markedly between individuals,
and again it's down to genes. Stephen Tsang of Columbia University in New
York City studies the genetics of responses to light intensity. He has
discovered that many of the genes involved in light perception come in
several different forms, and this can lead to huge individual variation in
light sensitivity. "Our response to light varies from those who can detect a
single photon to others who have a disease known as congenital stationary
night blindness, which severely impairs their ability to see in dim light,"
Tsang says. "Most of us living in the constant glow of cities don't realise
we might have some degree of impairment."
Colour perception, too, is hugely variable, and not just for the 8 per
cent of people (mostly men) with some degree of colour blindness. "Even
among individuals with normal vision, tests of colour perception show a wide
variation in how colours are seen," says geneticist Samir Deeb of the
University of Washington in Seattle, who studies colour vision. Again, most
of these differences appear to have a genetic basis.
Colour is detected by millions of cone cells in the retina and in a
normal person there are three types, responding to red, green and blue
light. This makes humans trichromatic and in theory allows us to distinguish
between more than 2 million different colours. Blue cones are very uniform
but there are at least four versions of the gene that encodes the red visual
pigment and four versions of the green. Because these genes are carried on
the X chromosome, and men have only one X chromosome, the variant genes are
readily expressed in men and often lead to subtle impairments in colour
vision.
But these variants don't just cause defects - they may give some women
enhanced colour vision. Because women have two X chromosomes, it is possible
for one X to carry the normal genes and the other to carry one or other of
the variants. This means some women have an extra type of cone, making them
potentially tetrachromatic. Deeb has now begun research on these
super-sighted women and says the phenomenon may not be unusual. "Around 15
per cent of women are carriers of colour vision deficiency," he says.
"Looking at 43 of these, two showed evidence of tetrachromacy."
So what does a tetrachromatic woman see that the rest of us don't? "I
wish I could tell you," laughs Deeb, although he says it is likely that they
are able to distinguish colours that mere trichromatics cannot. They could,
for example, be able to tell the difference between two seemingly identical
shades of green. Unfortunately, the rest of us will never know what we're
missing.
Meanwhile at McGill University in Montreal, Canada, mice are having
their tails dipped in hot water to study their reaction to pain. Jeffrey
Mogil's team has tested 12 strains of mice and found that while some strains
flick their tails out of hot water in 2 seconds, other strains take anything
up to 6. A series of experiments led him to conclude that this variation in
pain perception must be genetic, and he has now set out to find its source.
Recent evidence suggests that humans too have varying perceptions of
pain, and that those differences have a biological origin. Bob Coghill of
Wake Forest University School of Medicine in Winston-Salem, North Carolina,
took 17 volunteers and applied a heat source to the backs of their calves.
Then he raised the temperature in steps until it was 49 °C - about the most
human skin can take without burning - and asked the volunteers to rate the
amount of pain on a scale of 1 (no pain) to 10 (excruciating). The
variability in their responses was striking: some found a small temperature
rise unbearable while one subject did not feel any discomfort.
By repeating the experiment with the volunteers in an MRI brain
scanner, Coghill found a clear correlation between the amount of pain people
reported and the amount of brain activity that accompanies it in the
cerebral cortex. Those most susceptible showed much more activity. "The
perception of pain varies by a strikingly large amount," Mogil says, "and
these experiments show that those differences are real and objective."
Across at least four of the senses, then, there is enormous scope for
individual variation. Your combination of visual, olfactory, taste and pain
receptors is almost certainly different from mine. For Paul Breslin this
implies something profound. "If you consider that almost everything we learn
from birth is dependent on our sensory systems, then our individual sensory
differences are all the more interesting," he says. In other words, we are
partly a product of our senses. Breslin suggests that these differences
could even affect many of the choices we make in our lives. "There is a
significant visual and olfactory component in the kinds of foods we like,
the activities we take part in, the music we enjoy and even who we mate
with," he says. If that component is decided by our genes, the logical
conclusion is that, to some extent, we are genetically predetermined to
prefer certain things or people. Our freedom to choose is limited.
There are also implications for consciousness research. How the
physical world becomes our private sensory experiences - what philosophers
call "qualia" - is often seen as the key to understanding consciousness. So
if qualia are produced by the output of our senses, and people sense the
world in ways we can pin down objectively, does that help us understand
individual conscious experiences?
Possibly, says philosopher David Chalmers of the University of
Arizona. "We might one day be able to say that a person with a particular
set of genes has a particular type of consciousness," he says. But if this
is so, you have new problems to solve, "particularly when it comes to trying
to find out what someone else's consciousness is like". This question, known
as the "problem of other minds", also lies at the heart of consciousness
research.
The sensory world we live in is also complicated by the brain's
interpretation of what the senses are telling it. Rather than simply report
the output of our senses to the mind, the brain puts its own spin on the
world. In a dramatic demonstration of this, Daniel Simons of Harvard
University showed volunteers a video of a ball game and asked them to watch
one team intently. After about 45 seconds a woman dressed in a gorilla suit
walked in front of the camera. Around half the viewers completely missed the
gorilla. The rods and cones in their eyes obviously detected it, but their
brains chose to ignore it.
And so perhaps the age-old problem remains intractable. The red I see
might be different to the red you see, but perhaps our minds still interpret
the sensory input to give us a common red experience. You could say that
"red" will always be a pigment of the imagination.
Richard Hollingham
Moira de Swardt
"Peter H.M. Brooks" <fustbar...@e3.net.nz> wrote in message
> I am surprised that this breakthrough hasn't been discussed
here
> before. It seems that the question has now been answered, we do
not see the
> world in the same way, our qualia are personal. My red may be
quite a
> different quale from your red.
Qualia? Quale? Not listed in the Chambers Twentieth Century
Dictionary
> There are also implications for consciousness research. How
the
> physical world becomes our private sensory experiences - what
philosophers
> call "qualia" - is often seen as the key to understanding
consciousness. So
> if qualia are produced by the output of our senses, and people
sense the
> world in ways we can pin down objectively, does that help us
understand
> individual conscious experiences?
I'm aware that this has been explained above, but I would still like
a dictionary reference if one is available.
Moira, the Faerie Godmother
Peter H.M. Brooks
"Moira de Swardt" <moira.d...@wol.co.za> wrote in message
news:gfqdnb4lqsn...@is.co.za...
>
> "Peter H.M. Brooks" <fustbar...@e3.net.nz> wrote in message
>
> > I am surprised that this breakthrough hasn't been discussed
> here
> > before. It seems that the question has now been answered, we do
> not see the
> > world in the same way, our qualia are personal. My red may be
> quite a
> > different quale from your red.
>
> Qualia? Quale? Not listed in the Chambers Twentieth Century
> Dictionary
>
definition for qualia - though it does have a quote including it under
'pre-theoretical':
'So far as anything can be, qualia are pre-theoretical' - A.J Ayer, 1968
'Origins of Pragmatism
The OED has fallend down, I'm afraid, here. It does define the singular of
qualia, however, thus:
Quale: [L, neut. sing. of qualis of what kind] The quality of a thing; a
thing having certain qualities.
1675 [Bp Croft] Naked Truth 25 The quid, the quale, the quantum, and
such-like quacksalving forms.
a1679 T. Goodwin Govt. Ch. Christ. xi. Wks. 1697 IV. 94 The Quale, or what
sort of Bodies.. Christ hath instituted, is to be afterward discussed.
1768-74 Tucker Lt. Nat. (1834) II. 462 Qualities..cannot actually subsist,
though they may be thought of, without a quale to possess them.
1875 Jowett Plato (ed. 2) I. 270 When I do not know the 'quid' of anything
how can I know the 'quale'?
Better definitions by far are to be found in Philosophical Dictionaries
http://www.philosophypages.com/dy/ix3.htm#q for example gives:
qualia
The intrinsic phenomenal features of subjective consciousness, or sense
data. Thus, qualia include what it is like to see green grass, to taste
salt, to hear birds sing, to have a headache, to feel pain, etc. Providing
an adequate account of qualia is sometimes held to be a difficult problem
for functionalist explanations of mental states.
Recommended Reading: Leopold Stubenberg, Consciousness and Qualia
(Benjamins, 1998) {at Amazon.com}; Emotion, Qualia and Consciousness, ed. by
Alfred Kaszniak (World Scientific, 2001) {at Amazon.com}; Ming Singer,
Unbounded Consciousness: Qualia, Mind and Self (Free Assn., 2001) {at
Amazon.com}; and Joseph Levine, Purple Haze: The Puzzle of Consciousness
(Oxford, 2000) {at Amazon.com}.
Also see SEP, DPM, SEP, Daniel Dennett, David J. Chalmers, and Eric
Peter H.M. Brooks
>
> > I am surprised that this breakthrough hasn't been discussed
> here
> > before. It seems that the question has now been answered, we do
> not see the
> > world in the same way, our qualia are personal. My red may be
> quite a
> > different quale from your red.
>
> Qualia? Quale? Not listed in the Chambers Twentieth Century
> Dictionary
>
anyway, one of the very first threads on the subject of qualia (at
least on google) was by my brother. Here it is:
From: "Brooks, David" <BRO...@socsci.uct.ac.za>
Subject: The usefulness of qualia
Date: 1995/11/23
Message-ID: <m0tIZJu...@uctmail2.uct.ac.za>#1/1
sender: PSYCHE Discussion Forum <PSYC...@IRIS.RFMH.ORG>
priority: normal
comments: Gated by NET...@IRIS.RFMH.ORG
approved-by: "Brooks, David" <BRO...@SOCSCI.UCT.AC.ZA>
newsgroups: sci.psychology.consciousness
x-mailer: Pegasus Mail v3.22
What was the name of the film where Demi Moore sexually harrassed the
son of Kirk Douglas? In that film a virtual reality device enables
Douglas to track the villains through a computer. In real life he is
staggering around like an idiot with an absurd pair of goggles making
him blind. In the virtual world he is chasing another user around
stacks of files while new commands of "access denied" serve to bar
his passage through the innards of the machine.
If such a device were to be built one obvious explanation of its
usefulness would be that it provides information about its interior
geography etc. in a form that enables human beings, who have evolved
to deal with medium sized dry goods, to cope with it effortlessly and
efficiently.
Now some parts of the virtual world represent real
causes within the computer - when access is denied Douglas cannot get
to those file stacks-, others are mere flim flam. There is no
reason why the file stacks should look like filing cabinets. One
thing that is important is that there should be a way in which one
file stack could be told from another. Conveniently for Douglas
files are labelled and numbered. The real world has not been so
handily arranged (pace.Dr.Pangloss).
We are able to navigate through the real world because we
have a representation of it in our heads just as Douglas has a
representation of the insides of the computer in his head. We have
to be able to tell one bit of the representation from another.
Attending to some bits in a particular way will enable us to pick
tasty fruits from amidst thick foliage or to detect a poisonous
insect. These items are not conveniently numbered and labelled by
the creator. However they are colour coded. Brightly coloured
flowers and insects have evolved because making themselves
particularly salient to potential consumers confers advantages upon
them. They make themselves salient by adopting an outer covering
which makes them stand out in the interior world of those who might
eat them.
Qualia are inner labels, codes or filing tags. They are useful
because because in order to represent anything at all a representing
medium must be differentially responsive to differences in things
reprresented. (See Brooks 1992) Tags of this nature must on the one
hand be regularly associated with a distinctive class of external
things. They must also be such that the organism can distinguish
one from the other.
Organisms of a certain level of intelligence
are able to make flexible responses to the world. They can choose
alternative courses of action. They decide whether or not to eat the
red thing in the foliage according as it is a flower or an insect.
They do this we may suppose by responding to an internal
representation of the world. This inner map or model is
differentiated into different section by means of internal tagging
devices which have different properties FOR the orgasnism. Smells
colours and sounds delivering different information from different
sense organs have distinctively differentr FOR-the-organism labels.
Some information needs to be taken into consideration during high
level decision making. Other information may influence behaviour
without being explicitly tagged on the map at operational HQ. (The
naso-vomeral organ may convey qualialess smells such as pheromones to
lower than than conscious emotional motivators.)
FOR-the-organism tagging properties may be identified with nexuses
of functional and causal properties but should be expected to be
different from them. Devices which are able to represent and act
upon the world in a sufficiently flexible and intelligent way should
be expected to have such properties which should not be seen as any
threat to physicalism. One can only encounter the FOR-the-organism
tagging properties of another organism by merging with it and
becoming one and the same operational HQ.
David Brooks
D.Brooks 1992 "Secondary Qualities and Representation" Analysis 52
pp.174-179