Does Science Really Say There’s No Purpose to Life?
A new paper addresses the purpose of life from a cosmological perspective.
Posted Aug 04, 2017
Does humanity exist to serve some ultimate, transcendent purpose? Conventional scientific wisdom gives the answer as a definitive no. This is the answer provided in this recent New York Times piece ‘The universe doesn’t care about your purpose’, for example, and also by physicist Lawrence Krauss in his latest book. According to Krauss, the fact that we evolved on this planet is just a “cosmic accident”, and people who believe otherwise are probably suffering from some kind of religious delusion.
I don’t think this view of life is necessarily correct, however, even though my worldview is entirely naturalistic and I usually do agree with conventional scientific wisdom. As I explain in this article I published recently in the journal Complexity, I know of one possible mechanism by which life could, in fact, be endowed with a natural purpose. To understand this mechanism, it’s necessary to understand how natural selection works.
How biological natural selection creates 'purpose'
In biological selection, genes are selected to enable their own replication. Their ability to self-replicate, in turn, depends on how well they can encode traits—adaptations—which permit organisms to out-reproduce other members of their own species. The purpose (that is, function) of these adaptations is to solve complex problems (like seeing, digesting, mating, and thinking), and so they tend to be highly complex themselves. Improbable complexity is, in fact, the hallmark of natural selection, and the fundamental way in which we recognize that a trait actually is an adaptation (as opposed to being the by-product of an adaptation, or the result of random genetic ‘noise’).
Because improbable complexity is the hallmark of selection, organisms are the most improbably complex—that is, the least entropic—known things in the universe. Entropy is the degree of disorder in a physical system, and tends to increase in all such systems (that’s a basic law of physics known as the second law of thermodynamics). Entropy’s tendency to increase is the reason why, as Yeats said, "things fall apart": your new car or new suit, for example, tends to get more beat up rather than more pristine as times goes by. Because adaptations generated by natural selection are extraordinarily complex, they have extraordinarily low entropy, and selection is in fact the most powerful natural anti-entropic process known to science.
Biological natural selection explains how adaptations can have purpose (again, in the sense of function; for example, the purpose/function of an eye is to see), and why organisms can behave purposefully. It does not explain, however, how life in general could have any transcendent purpose, above and beyond the genetically-encoded interests of organisms themselves. That would require a higher-order explanation, and the Complexity paper presents what I regard as the most promising alternative of this sort. It’s an idea based on Lee Smolin’s theory of cosmological natural selection, which he first proposed in 1992 and presented most fully in his book The Life of the Cosmos.
The evolution of universes
Smolin founded his theory on the idea that our universe exists as just one in a vast population of replicating universes: a multiverse (this idea is becoming increasingly conventional and non-controversial among physicists). In a multiverse, Smolin reasoned, universe designs that were better at self-replication would achieve greater representation. And if black holes were the mechanism of self-replication, he reasoned further, then selection would favor universes that contained more black holes. From this perspective, life is merely the accidental by-product of processes ‘designed’ by cosmological natural selection to produce black holes.
Smolin’s theory has considerable intuitive appeal. It seems generally analogous to Darwin’s selection theory, and black holes do seem similar to the inverse of big-bang-type events: a black hole is an infinitely small concentration of spacetime, matter, and energy—a singularity—and a big bang is an explosive expansion of spacetime, matter, and energy, which emerges from a singularity.
In one glaring aspect, however, Smolin’s theory falls short of being analogous to Darwin’s: it does not predict that our universe’s most improbably complex (that is, least entropic) trait will be the one most likely to be an adaptation produced by cosmological natural selection. That trait is, of course, life itself. Smolin does recognize that life is the least entropic known thing (as he states in The Life of the Cosmos, “the entropy of a living thing is consequently much lower, atom for atom, than anything else in the world”), but his theory does not make the connection between entropy and adaptation. That is, it doesn’t acknowledge that just as improbably low entropy is the hallmark of selection operating at the biological level, we should also expect it to be the hallmark of selection operating at the cosmological level.
The truly novel aspect of my Complexity article is the explicit application of adaptationist theory to spell out exactly why life, as the least entropic known thing, is the most likely mechanism of universe replication. It’s not novel, however, to propose in more general terms that life, evolved to a sufficiently intelligent form, might constitute such a mechanism. Indeed, this general idea has been around nearly as long as Smolin’s theory itself, as described on this excellent ‘Evo Devo Universe’ site, and in this article I wrote recently. But it’s an idea that has never been developed or investigated as thoroughly as it deserved, and I hope that the Complexity article will help it to finally realize its potential.
The bottom line
The bottom line of both my Complexity article and this blog post is: life is more likely than black holes (or anything else) to be a mechanism of universe replication. Now if you've read this far, first of all let me thank and congratulate you, because I know this post discusses an esoteric topic using fairly technical language (I apologize for this language, but think it helps with precise communication). But let me also address a question that you may have at this point: "What could it possibly mean to suggest that life is a mechanism of universe replication?" I would start answering this question right now, but I've already gone on too long for a single post. So if you're interested in this topic, I hope you'll stay tuned for future posts.
Copyright Michael E. Price 2017. All rights reserved.