Hawking and Mlodinow, in the chapter of their book called “The Theory of Everything,” quote Albert Einstein: “The most incomprehensible thing about the universe is that it is comprehensible.” In response, Hawking and Mlodinow offer this crashing banality: “The universe is comprehensible because it is governed by scientific laws; that is to say, its behavior can be modeled.” Later, the authors invite us to give ourselves a collective pat on the back: “The fact that we human beings — who are ourselves mere collections of fundamental particles of nature — have been able to come this close to an understanding of the laws governing us and our universe is a great triumph.”
Great triumph or no, none of this addresses Einstein’s paradox, because no explanation is offered as to why our universe is “governed by scientific laws.” Moreover, even if we can be confident that our universe has unchanging physical laws — which many of the new speculative cosmologies call into question — how is it that we “mere collections of particles” are able to discern those laws? How can we be confident that we will continue to discern them better, until we understand them fully?
A common response to these questions invokes what has become the catch-all explanatory tool of advocates of scientism: evolution.
W. V. O. Quine was one of the first modern philosophers to apply evolutionary concepts to epistemology, when he argued in Ontological Relativity and Other Essays (1969) that natural selection should have favored the development of traits in human beings that lead us to distinguish truth from falsehood, on the grounds that believing false things is detrimental to fitness. More recently, scientific theories themselves have come to be considered the objects of natural selection. For example, philosopher Bastiaan C. van Fraassen argued in his 1980 book The Scientific Image:
the success of current scientific theories is no miracle. It is not even surprising to the scientific (Darwinist) mind. For any scientific theory is born into a life of fierce competition, a jungle red in tooth and claw. Only the successful theories survive — the ones which in fact latched onto actual regularities in nature.
Richard Dawkins has famously extended this analysis to ideas in general, which he calls “memes.”
The notion that our minds and senses are adapted to find knowledge
does have some intuitive appeal; as Aristotle observed long before
Darwin, “all men, by nature, desire to know.” But from an evolutionary
perspective, it is by no means obvious that there is always a fitness
advantage to knowing the truth. One might grant that it may be very
beneficial to my fitness to know certain facts in certain contexts: For
instance, if a saber-toothed tiger is about to attack me, it is likely
to be to my advantage to be aware of that fact.Accurate perception in general is likely to be advantageous. And simple mathematics, such as counting, might be advantageous to fitness in many contexts — for example, in keeping track of my numerous offspring when saber-toothed cats are about. Plausibly, even the human propensity for gathering genealogical information, and with it an intuitive sense of degrees of relatedness among social group members, might have been advantageous because it served to increase the propensity of an organism to protect members of the species with genotypes similar to its own. But the general epistemological argument offered by these authors goes far beyond any such elementary needs. While it may be plausible to imagine a fitness advantage to simple skills of classification and counting, it is very hard to see such an advantage to DNA sequence analysis or quantum theory.
Similar points apply whether one is considering the ideas themselves or the traits that allow us to form ideas as the objects of natural selection. In either case, the “fitness” of an idea hinges on its ability to gain wide adherence and acceptance. But there is little reason to suppose that natural selection would have favored the ability or desire to perceive the truth in all cases, rather than just some useful approximation of it. Indeed, in some contexts, a certain degree of self-deception may actually be advantageous from the point of view of fitness. There is a substantial sociobiological literature regarding the possible fitness advantages of self-deception in humans (the evolutionary biologist Robert L. Trivers reviewed these in a 2000 article in the Annals of the New York Academy of Sciences).
These invocations of evolution also highlight another common misuse of evolutionary ideas: namely, the idea that some trait must have evolved merely because we can imagine a scenario under which possession of that trait would have been advantageous to fitness. Unfortunately, biologists as well as philosophers have all too often been guilty of this sort of invalid inference. Such forays into evolutionary explanation amount ultimately to storytelling rather than to hypothesis-testing in the scientific sense. For a complete evolutionary account of a phenomenon, it is not enough to construct a story about how the trait might have evolved in response to a given selection pressure; rather, one must provide some sort of evidence that it really did so evolve. This is a very tall order, especially when we are dealing with human mental or behavioral traits, the genetic basis of which we are far from understanding.
Evolutionary biologists today are less inclined than Darwin was to expect that every trait of every organism must be explicable by positive selection. In fact, there is abundant evidence — as described in books like Motoo Kimura’s The Neutral Theory of Molecular Evolution (1983), Stephen Jay Gould’s The Structure of Evolutionary Theory (2002), and Michael Lynch’s The Origins of Genome Architecture (2007) — that many features of organisms arose by mutations that were fixed by chance, and were neither selectively favored nor disfavored. The fact that any species, including ours, has traits that might confer no obvious fitness benefit is perfectly consistent with what we know of evolution. Natural selection can explain much about why species are the way they are, but it does not necessarily offer a specific explanation for human intellectual powers, much less any sort of basis for confidence in the reliability of science.
What van Fraassen, Quine, and these other thinkers are appealing to is a kind of popularized and misapplied Darwinism that bears little relationship to how evolution really operates, yet that appears in popular writings of all sorts — and even, as I have discovered in my own work as an evolutionary biologist, in the peer-reviewed literature.
To speak of a “Darwinian” process of selection among culturally transmitted ideas, whether scientific theories or memes, is at best only a loose analogy with highly misleading implications. It easily becomes an interpretive blank check, permitting speculation that seems to explain any describable human trait. Moreover, even in the strongest possible interpretation of these arguments, at best they help a little in explaining why we human beings are capable of comprehending the universe — but they still say nothing about why the universe itself is comprehensible.
No comments:
Post a Comment