Date of last letter: 5 Dec 2007

December 17, 2007

Dear Colleague:  

    A historian struggles to find what happened in his hometown, say, one hundred years ago, with modest success at best even if his hometown is unusually rich in written and material records. Think how he envies the astrophysicist who knows precisely what happened at the birth of the universe, some fourteen billion years ago! Want to know what it was like a fraction of a second after the Big Bang? Well, a set of mathematical equations describe it to near perfection. With so much brain power and technical skill, you might think that the astrophysicist can also tell you what happened just before the noisy birth of the universe. Not at all. To one side of the time line, total knowledge; to the other side, total ignorance! Another limit to his knowledge lies near the other end of the story, when the first organism appeared. The physical scientist bows out, the biological scientist takes over. But not quite, for the biologist cannot explain the origin of life. Worse, the biologist has no overarching theory to guide his or her understanding of life's course of development in the first billion years—that is, before the appearance of a cell resembling a primitive bacterium that refused to share its genetic information with non-kin. Its offspring became the first species of bacteria. Several millions of years later, other cells resembling the primitive archea and eukaryotes appeared. They too refused to share, resulting in the competition for survival among non-interbreeding species. Then, and apparently only then, did Darwinian theory begin to apply to the evolution of life forms.

    The Darwinian reign lasted two to three billion years. Then came another challenge to the theory, the appearance of human intelligence—human intelligence as distinct from animal intelligence that is geared wholly to the needs of survival, and which, for that reason, is fully covered by Darwin's theory. Human intelligence in its highest development is something else. It is nature made self-aware, and what it is aware goes something like this. The earth is a minor planet circling around the sun; the sun is a modest-sized star, one of 100 billion, in our galaxy; and our galaxy is a modest-sized galaxy, one of 100 billion in the universe. That makes the Earth and us very small indeed, doesn't it? But worse is this. Apparently, all the billions of stars and all the billions of galaxies are mere sediments in the universe, covering perhaps a mere ten percent of its total content, which is made up of something called "dark matter." Now, how can an organic speck that is infinitely small and transient in the total scale of things arrive at this picture of itself and the universe? A biologist will need to explain the emergence of intelligence of this order; and if not quite that, then his own theory of evolution in causal terms of force. Explaining it in terms of the history of ideas obviously won't do, for the ideas are precisely what need to be scientifically explained, and not merely narrated and interpreted in the form of stories.

    There is a curious difference between the physical scientist and the biological scientist. The physical scientist is unhappy because his fundamental theory of nature (some mix of relativity and quantum mechanics) seems to work. He looks everywhere for evidence that contradicts Newton and Einstein. By contrast, the biologist gets antsy each time someone raises an objection to Darwin, and so shows himself to be almost as insecure as an Islamist foaming at the mouth over every perceived slight directed at Mohammed.

Best wishes,

Yi-Fu