1:03 p.m., Dec. 8, 2009----Rutgers philosophy professor Jerry Fodor spoke to an audience of some 200 University of Delaware faculty, students, and staff in the final lecture in UD's Year of Darwin Celebration, on Monday, Dec. 7.

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The talk “What Darwin Got Wrong,” which is also the title of a book co-authored by Fodor and scheduled for release in early 2010, focused on what Fodor sees as a fundamental error of logic in Darwin's theory of natural selection.

What Darwin got right, according to Fodor, was his first thesis: that common ancestry explains genealogy. This theory incorporates the idea that the distribution of phenotypes, or heritable traits, is not random. Thus, organisms can be plotted on a tree of resemblance, with those nearest one another on branches of the tree bearing the closest resemblance.

But, according to Fodor, Darwin was wrong about the mechanism that generates these tree structures over time.

“Darwin postulated that any phenotypic trait of a creature in a population is selected for its effect on fitness, or reproductive efficiency,” Fodor said. “This theory, known as natural selection, encompasses two components -- a random generator that produces a random assortment of traits in each new generation and an ecological filter that selects among these traits for relative fitness.”

For example, a trait like fur or feather color may evolve to make a creature more appealing to mates or less attractive to predators.

According to Fodor, the theory of natural selection went relatively unchallenged for more than a century. But in 1979, an assault on the underlying principle of the theory came from an unexpected front -- a paper that, on the surface, addressed an issue not in biology or genetics but in architecture.

Co-authored by Stephen Gould and Richard Lewontin, “The Spandrels of San Marco and The Panglossian Paradigm: A Critique of the Adaptationist Program,” ignited an argument about the foundations of selection theory that, Fodor said, shows no signs of abating.

What do spandrels have to do with evolution? The triangular spaces found at the junctures of arches in dome-type structures, spandrels are often decorated by artists. But unlike arches, which provide structural support for buildings and therefore are a trait connected with “fitness,” spandrels are merely a byproduct of arch-and-dome architecture, adding nothing to the fitness of the structure.

“Arches were 'selected' for holding up domes,” Fodor said. “Spandrels just came along for the ride. If the same is true of animals, then some traits can be present not as a cause of fitness but as a consequence of other traits that are the cause of fitness.”

“If there are co-extensive phenotypic traits,” he continued, “then natural selection can't do what it promised to do -- that is, predict or explain the relations between ecological variables and fitness.”

In other words, selection processes can't distinguish between arches and spandrels.

“Darwin was a very smart guy,” Fodor said, “so how did he get into this bind? The problem was that he equated artificial selection -- which can accommodate counterfactuals, or 'what-if' scenarios -- with natural selection, which cannot. The mind can do this, but nature can't.”

So to return to the arches and spandrels analogy, an architect can envision a building -- say, one made of titanium -- where spandrels wouldn't be along for the ride with arches.

“In nature, this is not possible,” Fodor said. “Only actual outcomes, not hypothetical ones, affect evolution.”

And that's where Darwin went wrong.

The State of New Jersey Professor of Philosophy at Rutgers University, Fodor has been a principal figure in cognitive science since its inception. Previously on the faculty at MIT, he has written such landmark works as Psychological Explanation, which helped invent the now dominant view of functionalism in the philosophy of mind.

The lecture was co-sponsored by the Center for International Studies, the Department of Linguistics and Cognitive Science, and the Department of Anthropology, with additional support from the Provost's Office, the College of Agriculture and Natural Resources, the Science, Ethics and Public Policy Program, and the following departments: Biological Sciences, English, Geography, Geological Sciences, and Philosophy.

UD's Year of Darwin Celebration launched last May in honor of the 200th anniversary of Charles Darwin's birth and the 150th anniversary of the publication of his landmark work On the Origin of Species. The series was organized by Karen Rosenberg, professor and chairperson of the Department of Anthropology.

Article by Diane Kukich