Science still can't explain the colour red

Michael Posner

Has the Western world succumbed to the disease of scientism – a misguided belief in the infallibility of science?

So says philosopher Peter Hacker, emeritus research fellow at Oxford's St. John's College. In a recent interview with TPM Online, the website of The Philosophers' Magazine, Mr. Hacker – a leading authority on Ludwig Wittgenstein – says scientism “pervades our mentality and our culture. We are prone to think that, if there's a serious problem, science will find the answer. If science cannot find the answer, then it cannot be a serious problem at all.”

This prevailing scientism, he continues “is manifest in the infatuation of the mass media with cognitive neuroscience … people nattering on what their brains make them do and tell them to do. I think this is pretty pernicious – anything but trivial.”

Mr. Hacker's remarks form part of a larger critique of how neuroscience is grappling with human consciousness, the great divide for philosophers and scientists.

Consciousness, of course, is one of the great, unsolved conundrums of modern science. Where, if anywhere, does awareness reside? How, if at all, can it be explained? Is the mind separate from its body? Or does everything, ultimately, reduce to biochemistry and quantum physics, including our private, inner-most experiences of the world?

From the time of Aristotle and Plato, these questions have largely been the preserve of philosophy. But the past several decades have witnessed the steady rise of cognitive neuroscience, which maintains that all human faculties, including consciousness, can now (or one day will) be explained by neural oscillations in the cerebral cortex – accountable by simple measurements of neurons and synapses.

As the late Francis Crick put it in his 1994 book, The Astonishing Hypothesis, “your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will are, in fact, no more than the behaviour of a vast assembly of nerve cells and their associated molecules.”

But the philosophers are refusing to go down without a good conceptual scrap. Mr. Hacker, for one, says it's nonsense to attribute consciousness, knowledge and perception to mere physical processes in the brain. “One sees with one's eyes and hears with one's ears,” he insists, “but one is not conscious with one's brain any more than one walks with one's brain. The brain is not an organ of consciousness. … The brain has no cognitive powers at all. There is no such thing as a brain's thinking, wanting, reasoning, believing or hypothesizing.”

Australian philosopher David Chalmers, now teaching in California, differentiates between what he calls the easy and hard problems of consciousness. Easy problems tend to be phenomena that can be explained by computational or neural mechanisms – recoiling from unpleasant odours, for example, or simply declaring “I am hungry” or some other mental state. The hard problem relates to the subjective qualities of human experience.

For instance, let's say you run into your old friend Jack. You register a moment of physical recognition: “Oh, there's old Jack.” But meeting old Jack also may trigger a series of “Jack” memories, emotions and ideas, all percolating more or less simultaneously. You may perceive that Jack has aged and remember how he once looked. You may recall beautiful music that Jack enjoyed, or the brilliant shade of red of the rose in Jack's lapel. The specific presence of Jack, in short, catalyzes the non-specific emergence of a holistic range of associations, drawn from some hidden well of private experience. You and you alone know what it is like to experience this moment of reconnection. It is literally incomparable.

“The hard problem is hard,” says Mr. Chalmers, “precisely because … the problem persists even when the performance of all the relevant functions is explained.”

Science can document all the processes involved in vision – electromagnetic waveforms striking the retina and proceeding electrochemically along the optic nerve to the brain's occipital lobe. But where does the felt experience of what is seen – let's say the colour red – come from? Says Mr. Chalmers: “There is an explanatory gap between the functions and experience.”

And the problem is hard, cognitive scientist Steven Pinker adds, because no one knows what the answer might look like “or even whether it is a genuine scientific problem in the first place.”

Indeed, many cognitive scientists, including Tufts University professor Daniel Dennett, challenge the notion of the hard problem and deny the very existence of so-called “qualia,” or of any ineffable internal life. Prof. Dennett contends that our notion of Self is simply “a cobbled-together collection of specialist brain circuits … that conspire to produce a virtual machine.” Other scientists, including Nobel Prize winner Gerald Edelman, accept the validity of qualia, but still regard consciousness as a biological phenomenon, emerging from the 100 billion neurons densely packed inside the brain. And some religious scientists, among them Nobelist Sir John Eccles, reject the brain-based view of consciousness as superstition; the spiritual, non-physical world we comprehend cannot be explained by dendrite or axonic activity alone.

Dozens of variations on these themes have been articulated, but the fundamental mystery of consciousness – and thus of human existence – remains.