Complexity: Some Assembly Required

Not long ago, in “Philosophy’s Burgess Shale,” I wondered whether, in the 21st century, there are more crazy ideas than usual. I suppose it depends where you look. For me, if any site reinforces this impression, it would be Quanta Magazine, where accomplished science writers attempt to summarize the latest developments in math, physics, biology, and computer science. I say “attempt” because the source material is often difficult and abstruse, although some writers are very good at explaining it in lay terms.

Recently, Philip Ball had a go at something called Assembly Theory, which tackles the problem of the origins of life (“A New Idea for How to Assemble Life”, May 4, 2023). It’s refreshing to see this acknowledged as a problem at all, because modern science usually pretends to take it in confident stride. But as Ball conveys the view of the researchers, Lee Cronin and Sara Walker, “complex molecules. . . in living organisms are far too complex to have been assembled by chance.” He later elaborates:

In accounting for specific, actual entities like humans in general (and you and me in particular), traditional physics is only of so much use. It provides the laws of nature, and assumes that specific outcomes are the result of specific initial conditions. In this view, we must have been somehow encoded in the first moments of the universe. But it surely requires extremely fine-tuned initial conditions to make Homo sapiens (let alone you) inevitable.

“Assembly Theory,” he explains, “escapes from that kind of overdetermined picture.” It does so by postulating that complexity develops along an accumulative chain, determined not merely by the simple laws of nature, but by an additional sort of racheting principle (although the article doesn’t use that term).

Ball points out a certain similarity to Chiara Marletto’s and David Deutsch’s “Constructor Theory,” which he has described in a separate Quanta article (“Physicists Rewrite the Fundamental Law That Leads to Disorder”, May 26, 2022). To the simple laws of nature, Constructor Theory adds the constraint of possible and impossible transformations, by invoking quantum superpositions that effect irreversible losses of information (since with each superposition, we are less able to say exactly where or when a given thing exists or happens). Assembly Theory turns instead to possible and impossible pathways of combination, mathematically conceived; the mechanism remains unidentified. Either way, nature is forced forward, its simple laws no longer able to act indifferently in either direction, and the development of complexity becomes possible.

There are two important aspects to Assembly Theory: the math, which introduces an “Assembly Index,” or “AI”—a quantification of the steps needed to create a certain level of complexity, which the researchers hope will be useful to distinguish life from non-life—and the process, which, as I suggest, is somewhat obscure. “According to Assembly Theory, before Darwinian evolution can proceed, something has to select for multiple copies of high-AI objects.” This “something” invites speculation. Perhaps Constructor Theory might be of help.

I began by suggesting we are in the realm of crazy 21st-century ideas, but as it turns out, the concepts common to Assembly Theory and Constructor Theory are at least a century old. Alfred North Whitehead outlined them in 1925, while discussing the religious reaction to Darwin’s theories.

By a blindness which is almost judicial as being a penalty to hasty, superficial thinking, many religious thinkers opposed the new doctrine; although, in truth, a thoroughgoing evolutionary philosophy is inconsistent with materialism. The aboriginal stuff, or material, from which a materialistic philosophy starts is incapable of evolution. This material is in itself the ultimate substance. Evolution, on the materialistic theory, is reduced to the role of being another word for the description of the changes of external relations between portions of matter. There is nothing to evolve, because one set of external relations is as good as any other set of external relations. There can merely be change, purposeless and unprogressive. But the whole point of the modern doctrine is the evolution of the complex organisms from antecedent states of less complex organisms. The doctrine thus cries aloud for a conception of organism as fundamental for nature. It also requires an underlying activity—a substantial activity—expressing itself in individual embodiments, and evolving in achievements of organism. The organism is a unit of emerging value, a real fusion of the characters of eternal objects, emerging for its own sake.” (Science and the Modern World, Mentor 1963 edition, p. 101.)

Whitehead spoke of “organism,” but the parallel with some definite drive toward complexity, and indeed with the general thrust of Assembly Theory and Constructor Theory, is discernible. While we may think in terms of quantum superposition to explain how simple laws of nature can become caught up in webs of interconnection (or mutual reflections, as Rovelli might say) through an apparent loss of information (since we can no longer say exactly where or when a “thing” happens), Whitehead thought more directly in terms of the interactions themselves. When everything is everywhere all the time, as I discussed in “Things Matter,” the weirdness of quantum superposition appears as a confusion predicated on the misplaced concreteness of “simple location.” As Whitehead tried to tell us, this confusion underlies, and ultimately undermines, the classical paradigms of philosophy and science.

Related Topics

Philosophy’s Burgess Shale, or the Return of Metaphysics
Things Happen
Evolution as Process

Additional Resources

A New Idea for How to Assemble Life (Philip Ball, Quanta Magazine)
Physicists Rewrite the Fundamental Law That Leads to Disorder (Philip Ball, Quanta Magazine)