Again, it flatters intuition. Most people have an intuition about consciousness as an integrated whole. Your various impressions and thoughts are somehow rolled together into a single inner you. That’s the impression we get, anyway.

You see this same trope in science fiction: If you bundle enough information into a computer, creating a big enough connected mass of data, it’ll wake up and start to act conscious, like Skynet. This appeal to our latent biases has given the integrated information theory tremendous currency. It’s compelling to many respected figures in the field of neuroscience, and is one of the most popular current theories.

And yet it doesn’t actually explain anything. What exactly is the mechanism that leads from integrated information in the brain to a person who ups and claims, “Hey, I have a conscious experience of all that integrated information!” There isn't one.

If you point a wavelength detector at the sky, it will compute that the sky is blue. If you build a machine that integrates the blueness of the sky with a lot of other information – the fact that the blue stuff is a sky, that it’s above the earth, that it extends so far here and so far there – if the machine integrates a massive amount of information about that sky – what makes the machine claim that it has a subjective awareness of blue? Why doesn’t it just have a bunch of integrated information, without the subjective awareness? The integration theory doesn’t even try to explain. It flatters our intuitions while explaining nothing.

Some scholars retreat to the position that consciousness must be a primary property of information that cannot be explained. If information is present, so is a primordial, conscious experience of it. The more information that is integrated together, the richer the conscious experience. This type of thinking leads straight to a mystical theory called panpsychism, the claim that everything in the universe is conscious, each in its own way, since everything contains at least some information. Rocks, trees, rivers, stars. This theory is the ultimate in phlegm theories. It has enormous intuitive appeal to people who are prone to project consciousness onto the objects around them, but it explains absolutely nothing. One must simply accept consciousness as an elemental property and abandon all hope of understanding it.

When I talk to other scientists about the study of consciousness, very often the first thing I’m asked to explain is why the topic is worth scientific attention. I argue that it’s not just a topic for philosophers or poets, and it’s not just a matter of opinion or belief. We can actually build rational theories of consciousness, theories that have explanatory power and that can be tested experimentally. And it’s crucial knowledge. Consciousness has a specific, practical impact on brain function. If you want to understand how the brain works, you need to understand that part of the machine. No neuroscientist, and no expert in artificial intelligence, should scoff at consciousness.