Letter to First Things November 1995: Pearcey, Nancy.

First Things 57 (November 1995): 2-5

Correspondence

Nancy Pearcey

The Fading of Positivist Belief

Contrary to a common misconception, science is not a monolithic enterprise committed to positivism. John J. Reilly ("After Darwin," June/July) is right on the mark in identifying the views of contemporary biologists such as Brian Goodwin as Platonic. In fact, from the time of the scientific revolution, biology has encompassed three major philosophical streams: Aristotelian, neo-Platonic, and mechanistic.

The Aristotelian approach held that organic structures must be understood according to built-in purposes (generally understood as divine purposes). Famous Aristotelians included Ray, Linnaeus, and Cuvier. But contemporary biologists are also giving Aristotle grudging credit; for example, Nobel prize-winner Max Delbruck delivered an address half-playfully entitled "How Aristotle Discovered DNA," arguing that the Aristotelian concept of Form is remarkably similar to the modern concept of a genetic program.

Brian Goodwin is a contemporary example of the neo-Platonist tradition, which emphasizes formative principles in living things and searches for fundamental anatomical patterns-"archetypes"-for each class of organism. Neo-Platonism blossomed in the eighteenth century as a reaction against the Newtonian world-machine of the Enlightenment, and was especially popular among embryologists, who sought an inner Law of Development to explain organic forms. (It is no accident that Goodwin is a developmental biologist.)

The mechanistic tradition began with Descartes, became radically reductionistic in the mid-nineteenth century, and achieved dominance in biology after Darwin proposed a completely materialistic mechanism for evolution. As historian Neal Gillespie argues, Darwin's intention was to promote a positivist epistemology limiting science to materialist explanations.

Today the neo-Darwinist mechanism for evolution (centered on mutation and natural selection) is being discredited-and with it, the positivist epistemology. As a result, the neo-Platonist tradition is becoming emboldened again, often encouraged by New Age spirituality (Goodwin's critics describe him as a New Age mystic); Aristotelianism is likewise making a comeback, particularly in creationist arguments for the validity of concepts such as purpose and design in biology.

Reilly seems worried about the sludge that might "bubble to the surface" as Enlightenment positivism cracks up. But I suggest that we are merely seeing a revival of the philosophical diversity that has always characterized biology. In the broad scope of history, the hegemony of positivism is a temporary aberration, a mere blip on the screen, already beginning to fade.

Nancy R. Pearcey Annandale, VA