At Medium, Prudence Louise, a writer on philosophy and religion, explains that in 1994 philosopher David Chalmers killed the Zombie in cold blood, igniting “a zombie apocalypse.” Sounds like an unusual role for a philosopher.

And the Zombie?: “The philosophical notion of a “zombie” basically refers to conceivable creatures which are physically indistinguishable from us but lack consciousness entirely (Chalmers 1996)” — Internet Encyclopaedia of Philosophy.

Louise asks us to picture that:

Imagine you meet your doppelganger. Someone physically identical to you, atom for atom. The only difference is the doppelganger has no inner consciousness. They look happy or sad, they even tell you of their hopes and dreams.

But there is nothing more than physical processes moving in response to physical causes. Their lips move and sounds which are meaningful to you come out, but they experience nothing at all. From the outside you are identical. But from the inside the zombie is a hollow imitation. That is a philosophical zombie. The physical structure, functions and behavior are identical, but there is no consciousness.

What exactly is the missing ingredient?

Prudence Louise, “The Impossibly Hard Problem of Consciousness” at Medium (October 30, 3021)

The zombie could, in principle, exist. At the same time, we all know we are not zombies in the sense that we know we are conscious more certainly than we know anything else. And if consciousness is an illusion, well, whose illusion is it?

As Louise goes on to show, for a physicalist (a person who believes that everything is physical), the zombie is an “explanatory nightmare.” It forces us to sense that there is something besides the physical.

Although we can explain more and more about the human body in terms of structure and function, there is no good science-based theory of consciousness on the horizon. And if we can explain everything about a human being except consciousness, well, we haven’t explained, say, the difference between Jane and Zombie-Jane, which humans generally agree is important.

As Louise explains in her short article, “The stakes are high. If there can’t be a scientific explanation of conscious experience, this shows physicalism is false.” One problem is that science explains third-person phenomena but consciousness is a first-person phenomenon. She then goes into much more careful logical and philosophical detail but here’s the gist:

When you move your body to the fridge in response to a desire for a snack, or take medication in response to pain, or lock the doors due to a fear of burglars, there is no causal connection between those conscious states and the physical effects of your body moving. This view isn’t fatal to the physicalist theory, but it puts it on critical life support. Our mental states cause actions which move matter constantly, giving us a lot of evidence it’s true. Any arguments those powers are illusory will need to be stronger than our confidence our conscious states cause our bodies to move.

Prudence Louise, “The Impossibly Hard Problem of Consciousness” at Medium (October 30, 3021)

Physicalism took root in a mechanistic view of the universe, pioneered by Isaac Newton. And before the Zombie even showed up, that view was already being challenged by quantum mechanics, in which the conscious observer plays a key role in what happens. But, for scientists, physicalism is not the only game in town:

Alternative metaphysics, like idealism, substance dualism or panpsychism all avoid the hard problem by denying causal closure. They accept the observation that consciousness is non-physical, and it’s causally effective, which means causal closure must be false. Unlike the observations of consciousness and its causal powers, causal closure isn’t based on observations of the world. It’s a metaphysical commitment. Physicalism is confronting a problem created by its philosophical commitments being in conflict with our observations of the world.

Prudence Louise, “The Impossibly Hard Problem of Consciousness” at Medium (October 30, 3021)

Of the three alternatives Louise lists, panpsychism seems to the one many scientists are gravitating to. Instead of “nothing is conscious,” many now think everything is conscious. Just recently, prominent biochemist James Shapiro titled a paper “All living cells are cognitive.” And prominent neuroscientist Antonio Damasio offered that viruses have some type of intelligence. Other well-known science achievers argue that electrons have a rudimentary mind.

In response to criticism from physicists Sabine Hossenfelder and Sean Carroll, philosopher Philip Goff points out that panpsychism is not in conflict with physics. It offers a simpler view of physics than dualism, with fewer gaps than materialism (including physicalism).

Essentially, panpsychism offers a way for scientists to address human consciousness, as currently understood, without explaining it away as an illusion. It would allow them to say that if Zombie-Jane existed, she would be missing something critical that Jane has (and so does everything else, to at least some extent).

Whether that benefit makes panpsychism a better explanation of reality than idealism or dualism is a separate question. Each of these points of view has its own issues but the Zombie isn’t one of them.

You may also wish to read: Theoretical physicist slams panpsychism Electrons cannot be conscious Sabine Hossenfelder’s view because they cannot change their behavior. Hossenfelder’s impatience is understandable but she underestimates the seriousness of the problem serious thinkers about consciousness confront. There is a reason that some scientists believe that the universe is conscious: It would be more logically coherent to say that you think the universe is conscious than to say that your own consciousness is an illusion. With the first idea, you may be wrong. With the second idea, you are not anything.