This Month's Talks :::
::: Life Without Definitions
Abstract: The question ‘what is life?’ is foundational to biology and especially important to astrobiologists, who may one day encounter utterly alien life. But how should we answer this question? The most popular strategy among both philosophers and scientists is to define ‘life’. I argue that this strategy is badly flawed on both logical and empirical grounds. What we need to answer the question is not a definition but an empirically adequate scientific theory of life. Yet we are in no position to formulate such a theory. Recent discoveries in molecular biology and biochemistry have revealed that familiar Earth life not only represents a single example but one that could have been at least modestly different in important ways at the molecular level. Moreover it is widely conceded by biochemists that we don’t know how different life could be given chemical and physical conditions very different from those on Earth. The upshot is that life on Earth today provides an empirically inadequate foundation for generalizing about life. The situation is not, however, as hopeless as it may seem. I sketch a strategy for procuring the needed additional examples of life without the guidance of a definition or theory of life, and close with an application to NASA’s fledgling search for extraterrestrial life.
|Revised 4/5/16 - Copyright 2006|