NOTES ON ALISTER MCGRATH,
“THE ENIGMAS OF EVOLUTIONARY BIOLOGY” (2009 GIFFORD LECTURE 4)
I.McGrath begins with the phenomenon of “biological fine-tuning,” which is the “idea that the universe appears to have possessed certain qualities from the moment of its inception which were favorable to the production of intelligent life on Earth at this point in cosmic history, life capable of reflecting on the implications of its existence. Nature’s fundamental constants turn out to have been ‘fine-tuned’ to reassuringly life-friendly values. The existence of carbon-based life on Earth depends on a delicate balance of physical and cosmological forces and parameter, which are such that were any one of these quantities to be slightly altered, this balance would have been destroyed and life would not have come into existence” (Lecture 2, pp. 16-17).
II.McGrath argues that “the emergence of life cannot be studied in isolation from the environment that creates the conditions and provides the resources that make this possible” (p. 3).
III.Consider two fundamental requirements for living systems:
(1) A self-maintaining metabolic system
(2) A genetic system capable of transmitting biological information
IV.A key philosophical question arises: Can evolution “be considered in any sense to be teleological”? (p. 4)
The answer depends on whether or not a teleological approach requires a priori metaphysical commitments.
V.There are three approaches to the philosophy of biology:
(1)Anti-teleological (Mayr, Dawkins, and Gould): evolution is an “open-ended and indeterminate process without any predetermined goal” (p. 4).
(2)A priori teleology (Bergson and Driesch): evolution has a “pre-established final goal” (p. 13).
(3)A posteriori teleology (Ayala and Conway Morris): evolution exhibits directionality (“organisms have generally become larger, more complex, more taxonomically diverse, and more energetically intensive” [p. 5]) and evolvability (“nature appears to select preferentially forms that are capable of future evolutionary development” [p. 8]).
VI.Gould and Conway Morris disagree on the question of contingency in biological evolution and “replaying the tape”; Gould uses the metaphor of evolution as a “drunkard’s walk.”
VII.Conway Morris argues for convergent evolution, with some examples:
(1)Photosynthesis
(2)The eye
(3)*Music and song
VIII.McGrath’s basic argument is that “some form of teleology emerges from the study of the evolutionary process itself. Such a teleology is empirical, grounded in a posteriori discernment, not a priori imposition. It is abducted from the observation of the evolutionary process, not deduced from a non-empirical metaphysical system. The term ‘teleology’ is more elastic than its critics appear to realize. It requires modification in the light of the empirical evidence, not abandonment in response to the dogmatic demands of those who maintain its inconceivability” (p. 16).
IX.So is atheism or is theism a better explanation of the emergence and evolution of life? It depends not on any difference in observation and experimental evidence but on which perspective, on other grounds, seems to offer a more satisfying interpretation. Compare the Dawkins/Noble disagreement over whether or not genes are “active” (p. 18).
X.In the last analysis, McGrath agrees with the British theologian John Henry Newman that “I believe in design because I believe in God; not in God because I see design” (p. 15).