Sunday, December 6, 2015

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: