What is consciousness, and does anyone actually know?

A Popular Mechanics article by Susan Lahey, Your Very Own Consciousness Can Interact With the Whole Universe, Scientists Believe, got me thinking about how little we actually understand about consciousness. The honest answer to "what is consciousness?" is that nobody knows. Neuroscientists, philosophers, and physicists all have theories, and they can't even agree on how to define the problem.

One theory that keeps coming up is Orchestrated Objective Reduction, or Orch OR. Roger Penrose, the Nobel laureate mathematician, and Stuart Hameroff, an anesthesiologist, proposed it in the 1990s. The basic idea: consciousness is a quantum event happening inside microtubules, the tiny structural elements inside neurons. They argue that quantum effects like superposition and entanglement occur in these microtubules, and that's where consciousness lives.

Most neuroscientists think this is wrong. The main objection is that the brain is too warm and wet for quantum coherence to survive. Quantum effects are fragile; they collapse when they interact with the environment. A brain at body temperature, full of ions and water, seems like the worst possible place for quantum computing.

But there's a counterargument. Quantum biology has found quantum effects in places we didn't expect. Photosynthesis, for example, appears to use quantum coherence to transfer energy with near-perfect efficiency. If plants can do it, maybe brains can too.

Some recent research has tried to test parts of the Orch OR theory. Jack Tuszynski's team ran computational simulations suggesting microtubules might sustain quantum coherence longer than critics assumed. A group at the University of Central Florida shined light on microtubules and observed prolonged re-emission, which could indicate stable quantum states. These are not proofs, but they're more than nothing.

I should mention that Penrose and Hameroff have collaborated with Deepak Chopra, which will raise eyebrows for anyone familiar with Chopra's history of using scientific-sounding language loosely. It doesn't invalidate the theory, but it does make me want to see more rigorous, independent testing before getting excited.

Meanwhile, Timothy Palmer at Oxford has proposed something different: that quantum mechanics is fundamentally geometric, and consciousness might be embedded in what he calls a fractal geometric state space. I don't fully understand it, and I suspect most people who claim to understand it don't either. But the idea that consciousness has a structure we could eventually describe mathematically is at least interesting.

None of this solves the hard problem of consciousness, which is why subjective experience exists at all. Why does it feel like something to be you? No theory, quantum or otherwise, has a good answer to that yet. We're still at the stage of arguing about what the question even means.

What I find interesting about Orch OR isn't that it's probably right. It's that it's testable, at least in principle. Most theories of consciousness are so vague you can't prove them wrong. This one makes specific claims about physical structures in the brain. If those claims turn out to be false, the theory dies. That's how science is supposed to work.