Hunting for qualia is Christof Koch's life. His scientific quest is the nature, location, and scientific description of consciousness. He tells the story of that quest in his book Consciousness: Confessions of a Romantic Reductionist.
Some early excerpts that capture the personal feel of the book:
At this point, I need to introduce qualia, a concept beloved by philosophers of mind. Qualia is the plural of quale. What it feels like to have a particular experience is the quale of that experience: The quale of the color red is what is common to such disparate percepts as seeing a red sunset, the red flag of China, arterial blood, a ruby gemstone, and Homer’s wine-dark sea.
In this book, I highlight stories from the front lines of modern research into the neurobiology of consciousness. Just as light presupposes its absence, darkness, so consciousness presupposes the unconscious. As Sigmund Freud, Pierre Janet, and others realized in the late nineteenth century, much of what goes on in our head is inaccessible to our mind— is not conscious.
I was born in 1956 in Kansas City, Missouri, one year after my brother Michael. Today, you can’t tell my Midwestern origin, as I retain a fairly strong German accent. We left two years later and started a peripatetic existence, staying four years in Amsterdam, where my younger brother, Andreas, was born. Subsequently, our family lived in Bonn, then the capital of West Germany. After elementary public school and two years at a Jesuit Gymnasium, it was time to move back across the Atlantic, to Ottawa.
In a lifetime of teaching, working, and debating with some of the smartest people on the planet, I’ve encountered brilliance and high achievement, but rarely true genius. Francis [Crick] was an intellectual giant, with the clearest and deepest mind I have ever met. He could take the same information as anybody else, read the same papers, yet come up with a totally novel question or inference. The neurologist and author Oliver Sacks, a good friend of us both, recollects that the experience of meeting Francis was “a little like sitting next to an intellectual nuclear reactor . . . . I never had a feeling of such incandescence.”
I believe that qualia are properties of the natural world. They do not have a divine or supernatural origin. Rather, they are the consequences of unknown laws that I would like to uncover.
Koch, Christof. Consciousness: Confessions of a Romantic Reductionist (MIT Press) (p. 28). The MIT Press. Kindle Edition.
The substance, embodied in specific experiments and observations, is tougher to capture in a brief excerpt, but here is one:
You are lying inside a cramped cylinder [an MRI scanner], desperately trying to keep still, to not even bat an eyelid, as any movement causes the signals to wash out. Through a mirror, you stare at a computer monitor displaying the ace of hearts from a deck of cards while the machine monitors blood flow in your brain. Neuroscientists are not good at sleight of hand, so they manipulate what you see by projecting a precisely timed second image into your eyes. If done well, this misdirection works as well as the magician’s— you won’t see the ace of hearts. The second image masks the first one, rendering the ace invisible. You look, but don’t see, inverting Yogi Berra’s famous witticism “You can observe a lot by watching.”
This technique was perfected by my then-graduate student Naotsugu Tsuchiya who called it continuous flash suppression. It works by projecting the image of the playing card into one of your eyes while continuously flashing a multitude of brightly colored, overlapping rectangles— like those of the Dutch painter Piet Mondrian— into the other eye. If you wink with this eye, the ace of hearts becomes visible, but if you keep both eyes open, the ace remains hidden for minutes on end, camouflaged by the ever-changing display of colored rectangles that distracts you.
Koch, Christof. Consciousness: Confessions of a Romantic Reductionist (MIT Press) (pp. 45-46). The MIT Press. Kindle Edition.
It can be shown that many portions of the brain receive the signal of the hidden card, but not the seat of consciousness. This in turn is related to the pattern of neuronal connnections between the visual processing centers of the brain and the absence of direct connections all the way to the prefrontal cortex.