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Kastrup: No, Consciousness CANNOT Be Just a Byproduct

Philosopher Bernardo Kastrup responds to biologist Jerry Coyne’s claim that consciousness could be a mere by-product of a useful evolved trait

Computer engineer and philosopher Bernardo Kastrup (left) has sparked considerable controversy lately by attacking a materialist view of consciousness. For example, recently he went on record as saying that consciousness can’t evolve in the way that an animal might evolve. Consciousness cannot even be measured in units of matter or energy. It is, he contends, a different sort of force. While some sources—Scientific American for one—have at least considered such views, materialists (naturalists) like evolutionary biologist Jerry Coyne (below right) have pushed back, insisting that consciousness could evolve as a byproduct (spandrel) of a trait useful for survival.

In architecture, a spandrel is a space created naturally by the curve of an arch, like l’Arc de Triomphe du Carrousel pictured below, where winged figures are appear in high relief in the spandrels. It has no weight-bearing function but is often decorated by artists in this way.

The implication of Coyne’s claim is that consciousness just happens to exist in a similar way, as a byproduct of a trait that promotes survival in humans.

Kastrup begins by emphatically restating his main argument:

The target of Jerry Berry’s latest rant and rage has been an essay I wrote claiming that, under the premises of mainstream physicalism, phenomenal consciousness—that is, subjective, qualitative experience—cannot have been the result of Darwinian evolution. The gist of my argument is that, according to physicalism, only quantitative parameters such as mass, charge, momentum, etc., figure in our models of the world—think of the mathematical equations underlying all physics—which, in turn, are putatively causally-closed. Therefore, the qualities of experience cannot perform any function whatsoever. And properties that perform no function cannot have been favored by natural selection.

Bernardo Kastrup, “Dim-witted biologist: consciousness is accidental” at BernardoKastrup.com (February 14, 2020)

He then responds directly to the argument that consciousness could be a spandrel:

I can imagine that some trivial and relatively low-cost (in terms of metabolism) biological structures and functions could be merely accidental, but the brain’s wondrous putative ability to produce the qualities of experience out of unconscious matter is anything but trivial. Indeed, it is nothing short of fantastic, the most stunning thing physicalists claim, the second most important unsolved problem in science according to Science magazine; and now it is a byproduct?!

Physicalists have no idea—not even in principle—how the material brain could possibly produce experience. Therefore, they appeal to—and hide behind—the inscrutable complexity of the brain with all kinds of promissory notes. Phenomenal consciousness—they argue—is somehow an emergent epiphenomenon of that unfathomable complexity. Fine. But if such is the case, it becomes unreasonable to posit that something requiring such a level of complexity could have been just an accidental byproduct of something else. One can’t have it both ways.

Bernardo Kastrup, “Dim-witted biologist: consciousness is accidental” at BernardoKastrup.com (February 14, 2020)

No doubt this debate has at least several more rounds to go. As a Big Topic, consciousness could turn out to be the most interesting debate of the millennial Twenties. We will try to keep readers posted.

Note 1: “Jerry Berry” is Kastrup’s soubriquet for Jerry Coyne, intended to mimick Coyne’s tendency to refer to intellectual opponents in a less than respectful way. Most commentators to date have simply ignored that element of Coyne’s public presence.

Note 2: the illustration immediately above of L’arc de Triomphe du Carrousel à Paris is courtesy Thesupermat, CC BY-SA 3.0

Leisurely but up-to-date reading on the consciousness clash:

Did consciousness evolve?: A Darwinist responds. Jerry Coyne argues that consciousness is a mere byproduct of useful traits that are naturally selected. But wait… The critical problem that consciousness poses for Darwinian evolution is that there is no survival advantage for subjective first-person existence over objective third-person existence.

Bernardo Kastrup: Consciousness cannot have evolved. How many joules of consciousness would make you a human instead of a chimpanzee? How many more joules of consciousness would make you a genius? Computer scientist and philosopher Bernardo Kastrup argues that evolution deals with things that can be measured quantitatively but consciousness cannot be quantified. 

Why would philosophers deny that consciousness is real? Because, says computer scientist Bernardo Kastrup, the materialism they are committed to makes no sense and that’s the best they can do.

Scientific American explores panpsychism… respectfully. This is a major change. At one time, a science mag would merely ridicule the idea of a conscious universe. Note: Make no mistake, panpsychism—as Goff elucidates it—is a purely naturalist view (“nothing supernatural or spiritual”). But, unlike the village atheist, he goes on to ask, but then what IS nature? Matter is all there is? But what IS matter? It turns out, no one really knows.


Panpsychism: You are conscious but so is your coffee mug. Or maybe not? A primer on varieties of panpsychism.

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Kastrup: No, Consciousness CANNOT Be Just a Byproduct