“Consciousness is that annoying thing that happens between naps.” This is how world-renowned philosopher and cognitive scientist David Chalmers defines the quintessentially human state in this debate, although his facetiousness is quite easy to detect: Chalmers famously formulated the “hard problem of consciousness” and built an immensely successful career around it. His views on consciousness are hardly that simple.

IAI Video: The Dance of Life (click to play)

In fact, Chalmers has elsewhere referred to consciousness as presenting a kind of paradox: “There’s nothing we know about more directly… but at the same time it’s the most mysterious phenomenon in the universe.”

Consciousness is indeed our most immediate and intimate experience. Perhaps no other human trait is at once so imminently close to us yet so remote and elusive when we try to grasp it conceptually. Although we spend most of our lives in a state of consciousness, as soon as we subject it to more careful scrutiny we realize that we know very little about it—how does it actually happen? And how does conscious experience fit into our scientific picture of the world?

In an attempt to answer some of these questions, The Institute of Art and Ideas has brought together cognitive scientist David Chalmers along with Peter Hacker (philosopher and critic of cognitive neuroscience) and Susanna Martinez-Conde (neuroscientist).

Although the questions formally asked in the debate are “Is experience all we have?” and “What is experience?,” these could have easily been phrased as “What is consciousness?” As Chalmers writes in his essay "Consciousness and its place in nature" (which you can read online here), “the hard problem of consciousness is the problem of experience” (2002, 247, my italics). Chalmers’s essay provides a great overview of the problem of consciousness and the mind-body corollary, and if the IAI debate sparks your curiosity on the topic, this a great resource to go to next. (There is also a PEL podcast episode called “What is the mind?” that refers to the Chalmers article quite often.) According to Chalmers, all human beings have subjective experience, i.e., “there is something it is like to be them.”. Apart from being signposted by "naps," that’s how we decide if a mental state is conscious—when there is something it is like to be in that state.

As we can see from the debate at the IAI however, for someone like Peter Hacker (a Wittgenstein scholar and an analytical philosopher) this question is at worst inane and ludicrous, and at best misleading. ‘What’s it like to have an experience?’ is a question that only seemingly makes sense grammatically, but upon analysis turns out that it doesn’t. Experience isn’t “like” anything. It’s not the same as seeing an opera, where you can ask “What was it like?” and answer by saying “Wonderful!” Asking "What is experience?" misleadingly assumes that experience is "a thing." Using a substantive induces the idea of substances, and makes us look for "things" where there aren’t any. Because of a misuse of language we start looking for chimeras, and when we can’t find anything, we hopelessly declare it a mystery.

But as Chalmers argues, our experience is a real thing and it is formed of everything from perceptions to emotions and thoughts. To describe what it is like to have these experiences, philosophers have come up with the term qualia. These are phenomenal properties that characterize our experience. Given the developments in neuroscience and the advances of the technology enabling us to study the brain, it seems that physical processes in the brain are indeed responsible for experience. So the hard question of consciousness is not only how do physical processes generate experience, but why is there a corresponding state of experience to these physical properties? Why is there a feeling that comes with the awareness of the sensory input?

In Consciousness and Its Place in Nature Chalmers divides the solutions to the hard problem of consciousness into reductive/materialist and non-reductive/non-materialist.

The neuroscientist’s perspective, as expressed in this debate, might fall under the former category. For Martinez, experience is generated in the brain, and the brain is part of the physical universe. Since the brain is governed by the same natural laws that govern the universe, then at some point in the near future we will be able to fully explain experience with neuroscience. Everything from how we perceive colors to the so-called "gut feeling" is fully explainable through neuroscience. Chalmers would call this view "type-A materialism," the kind of materialism where “there is no epistemic gap between physical and phenomenal truths” (id., p. 251).

Although Martinez does admit there are, at least for now, some limitations to what neuroscience can explain, and also admits scientists are primarily concerned with the "how," while the "why" is reserved for philosophers, most materialists think all this “mind talk” is complete nonsense. Science will be able to explain how physical processes give rise to experiences, and such an account will be based exclusively on natural principles. Phenomenal states are not ontologically different from physical states according to this view, and everything can be reduced to physical processes. Names like Gilbert Ryle, Stephen Stich, Paul and Patricia Churchland, as well as the popular Dan Dennett would fall in this category.

On the other hand, non-reductionist/non-materialists argue that subjective experience cannot be reduced to objective knowledge. The PEL episode “What is the mind?” is an attempt to make sense of both sides of the argument, in a fair and intellectually honest effort to grasp classic texts in the theory of mind (although it is particularly delightful to hear Wes lay into Ryle and Dennett, whom he—to put it elegantly—passionately disagrees with). As mentioned in the episode, arguments such as Frank Jackson’s Knowledge Argument and Thomas Nagel’s “What Is It Like to Be a Bat” are attempts to show that subjective experience cannot be reduced to objective knowledge. For instance, in the Knowledge Argument, we suppose there is a neuroscientist out there, named Mary, who is an expert on color perception, but has been brought up and lived exclusively in a black-and-white room. When she does go out and experiences the color red for the first time, she will have a fundamentally different experience from having studied and knowing everything about the color, which proves that science cannot account for all subjective experience. Perhaps it would have been interesting to hear Martinez’s neuroscientific take on this argument.

In Consciousness and Its Place in Nature, Chalmers also mentions the Knowledge Argument (along with many others) but he also proposes at least three alternatives to materialism that are compatible with a broadly naturalistic view of the world. Interactionism (i.e., the view that physical states cause phenomenal states and vice versa), epiphenomenalism (where physical states cause phenomenal ones, but not the other way around, and phenomenal states are ontologically different from physical ones), and finally, a type of monism where phenomenal properties are located at the fundamental level of physical reality and underlie physical reality itself.

As he mentions in the debate, Chalmers thinks neuroscience is primarily preoccupied with correlations, namely correlating experience with a so-called "neural correlative consciousness." While tracking down such correlations has tremendous value, it still doesn’t explain the connection between the objective reality and the subjective experience. For that, we need some kind of principle that bridges the gap, and only once we have that principle will we be able to explain the wonderful mystery of experience.

Ana Sandoiu is a writer and researcher living in Brighton, UK. You can follow her on Twitter @annasandoiu.