Luisi sobre a contingência e o determinismo na origem da vida

domingo, julho 03, 2011

P.L. Luisi

Contingency and Determinism

The Royal Society, Phil. Trans. R. Soc. Lond. A, 361, 1141-1147, 2003

By Pier Luigi Luisi

Department of Materials, ETH Zentrum,

8092 Zurich, Switzerland

Published online 2 May 2003

Contingency versus determinism is an old, classic issue in the history of science, and certain trends of contemporary science literature appear to be bringing it to the foreground again.

Keywords: contingency; determinism; origin of life; prebiotic chemistry; proteins



1. Inevitability

We generally accept the Oparin-Haldane scenario about the origin of life on Earth, according to which life was formed from inanimate matter throughout a long series of spontaneous steps of increasing molecular complexity, up to the formation of the ­ first self-reproducing protocells. From this scenario, any transcendent act or miraculous intervention is eliminated by definition.

How did this series of steps come about? One answer is in terms of determinism, according to which the laws of physics and chemistry determine the series of events sequentially and causally. Thus, in his book about the origin of life, Christian de Duve (1991) writes `given the suitable initial conditions, the emergence of life is highly probable and governed by the laws of chemistry and physics. . . ’.

This seems to lead one to the idea that life on Earth was inescapable, and in fact, in a more recent work (de Duve 2002), he restates this concept: `it is self-evident that the Universe was pregnant with life and the biosphere with man’. De Duve considers and discusses in this book the importance of contingency, but only limited to particular and secondary effects.

The idea of the inevitability of life on Earth, although phrased differently and generally with less emphasis, is presented by other signi­ cant authors, for example Herbert Morowitz, in his well-known book (Morowitz 1993, p. 12), states, `we have no reason to believe that biogenesis was not a series of chemical events subject to all of the laws governing atoms and their interactions’, adding also, interestingly, `only if we assume that life began by deterministic processes on the planet are we fully able to pursue the understanding of life’s origins within the constraints of normative science’ (Morowitz 1993, p. 3). He also adds a clear request against contingency: `we also reject the suggestions of Monod that the origin requires a series of highly improbable events and cannot be recovered from the laws of physics’ (Morowitz 1993, p. 13).