Pontifical Catholic University of Chile neuroscientist Francisco Aboitiz offers a free excerpt from his forthcoming book, A History of Bodies, Brains, and Minds: The Evolution of Life and Consciousness (MIT September 2024).

He begins by looking at the two most prominent theories of consciousness:

It is not possible to do justice to all the theories of consciousness, so I focus on two prevalent ones that have been the most discussed in recent years—the integrated information theory (IIT) by Giulio Tononi and the global workspace theory (GWS) by Bernard Baars and Stan Franklin. The IIT refers to an encapsulated network in the brain with such high interconnectivity that it works as an indivisible whole. The GSW, on the other hand, proposes a globalized space where different cognitive processes converge to generate a multidimensional map from which decisions and courses of action are produced.

Francisco Aboitiz, “How did consciousness evolve?,” The Transmitter, August 26, 2024

One thing Aboitiz doesn’t mention in the excerpt is that the two theories were pitted against each other in 2019 in a historic five-year contest. But alas, it did not prove possible to declare a winner in 2024:

The event has received mixed reviews. Some researchers point to the failure to meaningfully test the differences between the two theories. Others highlight the success of the project in driving consciousness science forward, both by delivering large, novel, skillfully executed data sets and by inspiring other contestants to engage in their own adversarial collaborations.

Elizabeth Finkel, “What a Contest of Consciousness Theories Really Proved,” Quanta, August 24, 2023

That level of uncertainty surely thwarts the conventional tools of research.

What about consciousness in animals?

With animals, he addresses the ethical issue of inflicting pain:

It may become illegal to boil living lobsters, but will it come a point where we cannot eat them, together with mollusks, fish, chicken, cattle and even insects? Where do we draw the line?

Aboitiz, “Evolve?”

The problem is that we don’t know if insects, for example, do feel pain. An alarm can go off in an empty building and set in motion a series of automatic events that nothing is actually experiencing. In that sense, a life form might act to avoid harm without feeling anything.

Aboitiz senses a similar problem when he talks about the “mirror test” — the hypothesis that life forms must have self-awareness, a form of consciousness, if they can recognize themselves in a mirror:

The experiments of self-recognition in a mirror were initially used to verify self-consciousness, but it was found that some fishes can pass the mirror test, suggesting that this ability is based on simple brain mechanisms…

Aboitiz, “Evolve?”

He is onto something there. For one thing, the test gives dubious results the other way too. Only a few dogs, for example, pass the mirror test but hardly anyone doubts that dogs are self-aware. He admits, “All in all, research in animal consciousness faces the same challenges as the study of human consciousness.”

A startling admission

Aboitiz concludes, “In the end, the dualistic dilemma between subjective experience and mechanistic explanations seems to me inescapable.” Perhaps the key word here is “mechanistic.” If a type of consciousness is not a mechanistic phenomenon, it won’t have a mechanistic explanation.

Is panpsychism a way forward?

One alternative to get away from the mind-body conundrum has been pan-psychism, which is an extension of the identity hypothesis, proposing that some degree of consciousness is a feature of the universe like energy or gravity are. As prescribed by the IIT, the subjective experience may be a widespread phenomenon among living beings that amplifies with the increase in complexity, and in particular may have exploded like a ‘big bang’ with the origin of large brains, giving rise to fully subjective consciousness.

Aboitiz, “Evolve?”

Here we see clearly the way that panpsychism — which some may assume is a mystical concept — is, on the contrary, invoked to head off the impossible conundrums of consciousness while remaining within naturalist science.

Panpsychism could simply replace eliminationism as a bedrock assumption. On that view, a proper scientific explanation does not eliminate the idea of consciousness from science but rather grounds it in basic components of the universe. Many “prestigious authors,” he notes, look hopefully at quantum theory to do the job. He isn’t happy with panpsychism or quantum consciousness but he understands the problem.

A startling admission

Unlike many neuroscientists, Aboitiz is prepared to admit to the existence of human uniqueness: “We need to keep present that our mind is practically unique (at least on Earth), and results from having an extremely complex brain endowed with language.” Of course, that admission limits a vast array of hypotheses that seek answers to the behavior of the human mind in the behavior of the animal mind.

At the end of the excerpt, he proposes to tell us “where evolution may lead our species, our brains and our minds.” But that, of course, raises another question.

What evidence have we that human consciousness did evolve?

Our minds’ exceptionality remains inescapable. But just as eliminationism proposed to explain away the human mind, evolution theory posits that it must have evolved without any sense of a need to offer either further argument or evidence. After that, the only task required of the evolutionist in this case is a speculative history — filling in the blanks more cleverly than another theorist might. Aboitiz’s effort may be one of the more promising ones, if only because of the concessions he is prepared to make to the reality of the mind.

But we have no particular reason, at present, to assume that the human mind evolved at all.