Last Friday I went to a talk given by a world-renowned evolutionary biologist at Harvard Medical School. At the beginning of the talk, the speaker methodically provided an overview of the development of evolutionary biology, both from the theoretical and empirical perspective. It was precisely when he attempted to address the historical transition from Darwin’s natural selection to Kimura’s neutral theory that one of the audience (a world-renown physicist at Harvard) made a comment that Wallace should’ve been included in Darwin’s clan. I sort of shuddered and made a frivolous rebuttal to argue otherwise. Well, the atmosphere was gaily and casual, so the talk went on. But that incident did impel me to ponder what do I make of things I uttered.

Most people would agree that Wallace is the co-developer of the theory of natural selection. However, it is less known that his stance on evolution diverged from that of Darwin’s when it comes to whether evolution is sufficient to explain human’s mind. Unlike Darwin, he believed that there’s no way it can be construed within the framework of evolution based on natural selection. Instead, it can only come from the design of some superior existence or intelligence. And only through the mind can a man escape the shackles and scourge inflicted by the deterministic world. This belief, seems spiritualistic, indeed engrossed him to spend his later life in finding ways to communicate with the dead.

As a theoretical biophysicist, I’m more inclined to believe that there is a theory (or many plausible theories) of the human mind, but what I’m not sure about is whether our current understanding of evolution is sufficient to do it justice. Darwin’s theory is by itself a beautiful theory based on empirical observations and was proposed way before the genomic era. It is based on the idea of natural selection whereby organisms that are good at reproducing in given environments are favored. Through natural selection, specific “traits” can be maintained and passed down to the offspring, a process dubbed adaptation. In the materialist world, it is fairly easy to understand what traits are likely to survive natural selection and what is not. But with our mental life, particularly in the social realm, the function of mental faculty is not always conducive to explanations, let alone being placed under the spotlight for scrutiny under the lens of natural selection. For example, would we be better off by living a monogamous or polygamous life? Should we be cooperative or selfish? The staunch disciple of Dawkins might spout off that natural selection is a process that is impervious to morality and social norms. What really matters is which genes outperform their adversaries and come to prevail in population. If this is true, shouldn’t men be lining up outside of sperm banks so that they have better chance to maximize their reproduction success?

Steven Pinker argued, there’s a difference between the mechanisms that impel organisms to behave in real time and the mechanisms that shaped the design of the organism over evolutionary times. At the long evolutionary time scale, it is perhaps fair to argue that we’re programmed by our biology to follow what Darwin expected (i.e., ultimate causation). Whereas in the shorter time scale, we need something to explain our real-time desire to conduct specific behaviors (i.e., proximate causation), be it pertinent from the evolution point of view or not.