Feinberg and Mallatt’s Ancient Origins of Consciousness

Neurologist/psychiatrist Todd Feinberg and evolutionary biologist Jon Mallatt propose that consciousness appeared much earlier in evolutionary history than is commonly assumed, and therefore all vertebrates and perhaps even some invertebrates are conscious.

By assembling a list of the biological and neurobiological features that seem responsible for consciousness, and by juxtaposing the fossil record of evolution, the authors argue that about 520–560 million years ago, “the great ‘Cambrian explosion’ of animal diversity produced the first complex brains, which were accompanied by the first appearance of consciousness; simple reflexive behaviors evolved into a unified inner world of subjective experiences” (Feinberg & Mallatt, 2016).

From Single Cells to Primitive Brains

Doing what they call “neuroevolution,” Feinberg and Mallatt put forth the even more unconventional idea that the origin of consciousness goes back to the origin of life, in that single-cell creatures respond to stimuli from the environment, whether attracted to food sources or repelled by harmful chemicals. The authors call this process “sensory consciousness” [but which others may call stimulus-response patterns unworthy of the “consciousness” appellation]. In addition, the cell membrane distinguishes self from non-self, which becomes another baby step on the long evolutionary journey to human consciousness.

A crucial developmental step, they say, was the evolution of “hidden layers” of clusters of intermediary nerve cells that process and relay internal signals between sensory-input and motor-output nerve cells. Driven by evolutionary pressures, these clusters would go on to evolve into primitive and then more complex brains (Feinberg & Mallatt, 2016; Rose, 2017).

If indeed these were the historical facts, it would naturally follow that “all vertebrates are and have always been conscious—not just humans and other mammals, but also every fish, reptile, amphibian, and bird.” Moreover, Feinberg and Mallatt find that many invertebrates—arthropods (including insects and probably crustaceans) and cephalopods (including the octopus)—"meet many of the criteria for consciousness.” Their proposal challenges standard-model theory that “consciousness evolved simultaneously but independently in the first vertebrates and possibly arthropods more than half a billion years ago.”

Combining evolutionary, neurobiological, and philosophical approaches enables Feinberg and Mallatt to cast a broader group of animals that are conscious, though it is less clear how their theory offers—as the marketing claims, the authors less so—“an original solution to the ‘hard problem’ of consciousness” (Feinberg & Mallatt, 2016).