- The Rest is Silence*
Genetic reductionism and its "spouse"—genetic determinism—celebrated their alleged victory in the Human Genome Project. We were told that very soon the "Book of Life" would be open and ready for reading. After only a short time on this planet, Homo sapiens seemed to have solved the biggest riddle of all: what is life? However, things are always more complicated than they seem at first glance, and critical biologists like Evelyn Fox Keller and Richard Lewontin were quick to point at the shortcomings of the reductionist venture. The criticism can be roughly summarized as follows: Life is complex! Organisms are more than just a bunch of (selfish) genes or cells, just as a text is more than a bunch of words and a piece of music is more than a bunch of chords. Biological systems have the gestalt property of a whole that is different from the sum of its parts. Therefore, studying biological systems means more than breaking the system down into its components and focusing on the digital information encapsulated in each cell. Studying biological systems also involves examining how digital information turns into biological meaning and how biological components are orchestrated through various interactions to constitute the living whole. The idea that living systems should be studied as wholes is the basic axiom of what is known as the systems perspective in biology.
In his book The Music of Life, Denis Noble presents the systems biology perspective with an intelligent, authoritative, and realistic voice. Noble (b. 1936) is [End Page 625] a distinguished physiologist who made a pioneering work in modeling the heart. Being both an experimentalist and a theoretician, he uses his knowledge, experience, and scientific achievements to establish a strong argument in favor of systems biology, the theoretical approach urging us to study biological phenomena as the system-level behavior of micro-level interactions. According to this approach, the heartbeat is not determined by a "top-down homunculus." As in other biological systems, the heartbeat is primarily governed by bottom-up interactions and feedback loops. Like the order of applause emerging from the audience clapping its hands in a concert or the synchronization of fireflies, the logic of the heart is not the logic of a single governor but of a coordinating collective. In this context, computational modeling is an indispensable tool of inquiry. If the system is too complex for our limited minds, let's extend the limit of our minds by using an artifact, the computer.
Nobel does not dismiss the proven achievements of genetic reductionism but argues for the necessity of the systems perspective. This is not an easy task. There is always a naïve reductionist ready to knock down the straw man of systems biology by asking: "The world is complex; is this reason for not studying it? And what is the alternative that you, my dear opponents, suggest? A kind of a non-scientific holism?" As a strategy for facing this expected response, Noble frames his arguments in a musical metaphor. This is a clever move, because unlike what some people think, a metaphor is not just a rhetorical ornament but a way of thinking. Cognitive linguistics, a school of linguistics that suggests that human language should be studied as a cognitive phenomenon, posits that the way we use our language is intermingled with the way we construct our knowledge. George Lakoff, a leading figure in cognitive linguistics, has shown that human thinking is grounded in metaphors that underlie and mediate our conceptual knowledge. Introducing a new metaphor is therefore introducing a new way of thinking. But why music as a source of metaphors? In his book of collected essays, Music at Night, Aldous Huxley (1949) writes: "all the things that, to the human spirit, are the most profoundly significant, can only be expressed. The rest is always and everywhere silence. After silence that which comes nearest to expressing the inexpressible is music" (p. 19). Music is systemic in nature, and Noble's decision to use it is justified as an instructive way...