Margaret Wertheim - I feel therefore I am
How exactly did consciousness become a problem? And why,
after years off the table, is it a hot research subject now?
Everyone agrees that the sky is blue, but how could I know
that what I experience as blue isn’t what you experience as red? Philosophers
have long been similarly perplexed. In An Essay Concerning Human
Understanding (1690), John Locke wondered if ‘the same object should
produce in several men’s minds different ideas at the same time; for example,
the idea, that a violet produces in one man’s mind by his eyes, were the same
that a marigold produced in another man’s, and vice versa.’ Now known to
philosophers of mind as the inverted spectrum argument, Locke’s query points us
to the mystery of subjective experience and its attendant problem of
‘consciousness’.
Objectively speaking, physicists have an explanation for
what blue is. According to Maxwell’s equations, blue is ripples of
electromagnetism with a wavelength of between 450 and 495 nanometres. A triumph
of modern science, the wave understanding of colour allows us to determine the
makeup of stars that are billions of light years away and assay the chemical
compounds for their constituent elements. Yet the very success of this
explanation highlights a conundrum; for while any spectrometer can register
blue precisely on a dial, few of us would say that it is conscious. A
spectrometer does not perceive blue. So what then, does it
mean to be ‘conscious’ of colour?
First coined in 1995 by the Australian philosopher David
Chalmers, this ‘hard problem’ of consciousness highlights the distinction
between registering and actually feeling a phenomenon. Such
feelings are what philosophers refer to as qualia: roughly
speaking, the properties by which we classify experiences according to ‘what
they are like’.
In 2008, the French thinker Michel Bitbol nicely
parsed the distinction between feeling and registering by
pointing to the difference between the subjective statement ‘I feel hot’, and
the objective assertion that ‘The temperature of this room is higher than the
boiling point of alcohol’ – a statement that is amenable to test by
thermometer.
It might seem surprising to many readers but, for 300 years,
scientists and philosophers have been debating whether our minds might not
operate more like Bitbol’s thermometer. Though Chalmers’ ‘hard problem’ term is
new, the questions underlying it have haunted modern science from its
beginnings, for the attribution of consciousness is one of the foremost
qualities distinguishing us as something other than a complex
set of dials.
As one of the founders of empiricism, Locke believed that
knowledge comes primarily from sensory experience, with real knowledge being felt by
conscious beings. In the 17th century, René Descartes had also insisted on the
irreducible centrality of subjective experience, arguing that, in principle, we
could not build a machine to emulate human behaviour. For Descartes, a
conscious machine was an impossibility, and something extra – a soul – was
needed to account for the full spectrum of our mental landscape and actions.
Like Chalmers and Bitbol today, Descartes and Locke considered conscious
experience as something that couldn’t be wholly explained by the laws of
physical nature.
But in the early 18th century an emerging group of
mechanists began to suggest that feelings and emotions were merely secondary
byproducts of the ‘true reality’ of matter in motion. On this view, expressed
by Julien Offray de La Mettrie in L’homme machine (1748),
humans are essentially meat machines, complicated to be sure, but ultimately
the same order of being as an expensive watch. The purpose of science was to
discover the laws by which matter behaves, and thus the whole question of the
conscious self – the ‘I’ that feels hot and blue – was not so much a problem as
an irrelevancy.
The idea that the laws of nature might be able to account
for conscious experience – a position known as physicalism –
steadily gained supporters in the 19th century and was given a particular boost
with the advent of Maxwell’s equations and other powerful mathematical
frameworks devised by physicists in their golden age. If the invisible field of
a magnet can result from natural laws, then might the same not be true for
feelings?
Yet, as some philosophers of the early 20th century began to
point out, physicalism contains a logical flaw. If consciousness is a secondary
byproduct of physical laws, and if those laws are causally closed – meaning
that everything in the world is explained by them (as physicalists claim) –
then consciousness becomes truly irrelevant. Physicalism further allows us to
imagine a world without consciousness, a ‘zombie world’ that looks
exactly like our own, peopled with beings who act exactly like us but aren’t
conscious. Such zombies have no feelings, emotions or subjective experience;
they live lives without qualia. As Chalmers has noted, there is literally
nothingit is like to be zombie. And if zombies can exist in the
physicalist account of the world, then, according to Chalmers, that account
can’t be a complete description of our world, where feelings do exist:
something more is needed, beyond the laws of nature, to account for conscious
subjective experience.
These are fighting words. And some scientists are fighting
back. In the frontline are the neuroscientists who, with increasing frequency,
are proposing theories for how subjective experience might emerge from a matrix
of neurons and brain chemistry. A slew of books over the past two decades have
proffered solutions to the ‘problem’ of consciousness. Among the best known are
Christof Koch’s The Quest for Consciousness: A Neurobiological Approach (2004);
Giulio Tononi and Gerald Edelman’s A Universe of Consciousness: How Matter
Becomes Imagination (2000); Antonio Damasio’s The Feeling of
What Happens: Body and Emotion in the Making of Consciousness (1999);
and the philosopher Daniel Dennett’s bluntly titled Consciousness
Explained(1991).
It has been said that, if the 20th century was the age of
physics, the 21st will be the age of the brain. Among scientists today,
consciousness is being hailed as one of the prime intellectual challenges. My
interest in the subject is not in any particular solution to the origin of
consciousness – I believe we’ll be arguing about that for millennia to come –
but rather in the question: why is consciousness perceived as a ‘problem’? How
exactly did it become a problem? And given that it was off the table of science
for so long, why is it now becoming such a hot research subject?
Medieval theologians did not sit around debating the
ontological status of zombies. They knew for a fact that humans are conscious
and built a system of control and punishment around this principle. The
Catholic Church tortured people for committing theological crimes over which
they supposedly had conscious choice – the most salient being errors of faith:
did one believe (as one should) in the Trinity of God, or in the heretical
notion of Unitarianism?
Torture was a method of mind control premised on a
worldview in which conscious minds are morally accountable. Zombies, by
contrast, have no real minds and no moral compass: they are neither good nor
bad. Since they don’t feel pain in any meaningful sense, torturing a zombie
would be pointless. What makes them such formidable foes on screen is that
zombies are beyond the limits of subjectivity. We don’t feel for them because they don’t
feel. Robots belong to the same order of being. Only when we think bots are
developing consciousness (as in Blade Runner and Ex
Machina) does our treatment of them become an issue.
Pain and suffering were very present aspects of the European
mental landscape in the Middle Ages, and were graphically depicted in
representations of Hell (think of Giotto’s Arena Chapel), thereby reminding
would-be sinners of the torments awaiting them in the afterlife if they didn’t
make the right moral choices here on Earth. For medieval Europeans,
subjectivity extended beyond the grave. And that was the point. Self-awareness
wasn’t an end in itself, it was a mechanism by which humans with their eternal
souls were embedded in a cosmic scheme linking everything to an Ultimate Good.
Heaven and Earth were two separate yet intertwined domains of human action.
Medieval cosmology was thus inherently dualistic: the physical domain of the
body had a parallel in the spiritual domain of the soul; and for medieval
thinkers, the latter was the primary domain of the Real.
You could literally read the moral status of people in
medieval images by their scale. Jesus would be drawn as the largest figure
because he had the greatest moral stature; next came angels who were somewhat
smaller, followed by saints and martyrs, then ordinary humans. Smallest of all
were the sinners in Hell who, in Giotto’s rendition, are minute figures focused
in their pain, hemmed in by their puny morals. In contrast with the bleakness
and blackness of Hell, Heaven was often portrayed in a gorgeous shade of blue,
achieved through costly pigments containing ground lapis lazuli and other
precious stones that metaphorically signalled the value of redemption. Blue,
here, was the wavelength of God.
When modern science swept away this dualistic symbolic
schema, Europeans came to see themselves as inhabitants of a Euclidean void: we
lived on a planet that orbited an insignificant star in potentially infinite
space. As described by geometry and physics, this space was understood to be
controlled by mathematical laws. And, in this despiritualised, Euclidean space,
human figures, including Christ and the saints (now equally subject to natural
law) were necessarily depicted at the same scale.
The homogeneous,
featureless Euclidean void, which forms the backdrop to Galilean and Newtonian
science, has its visual correlate in the homogeneous scheme of perspectival
representation that unified earthly and heavenly space. Now all objects were
placed within a single frame of reference. Perspective,
delightfully known in the 13th century as ‘geometric figuring’, enabled artists
to simulate the illusion of physical depth, but it removed the metric by which
they had previously represented moral depth. Just as art became literal rather
than iconic with the advent of modern science, our concept of a moral universe
became subject to homogenisation, and finally to a kind of erasure.
Once we take our universe to be a mathematical arena, a
question arises as to where in this scheme the realm of the soul might be
found. Specifically, in an infinite despiritualised Euclidean universe there is
no room for Heaven. Indeed it now becomes problematic to talk about any place beyond the
physical realm. This hadn’t been an issue with the medieval cosmos, which was
finite. As depicted in pre-Renaissance imagery, the medieval cosmos was a
relatively small place, with the Earth at the centre surrounded, onion-like, by
a set of concentric spheres carrying the Sun, Moon, planets and stars. Beyond
the outermost sphere of the stars, there was metaphorically plenty of space
left for the Empyrean Heaven of God.
At the end of The Divine Comedy (1320),
when Dante reaches the end of the physical world, he pierces the cosmic skin
and emerges into the presence of ‘the Love which moves the sun and the other
stars’. But with the arrival of the Newtonian universe, the problem of Heaven’s
‘location’ was compounded into a geographical absurdity... Read more:
