The philosopher Daniel Dennett has recently published a memoir and in a review Matthew Lau accuses him of pursuing a ‘dead end social Darwinism’. He says that Dennett has defended the idea of ‘adaptationism’, the view “that all features of an organism must be adapted for some good purpose.” This has been rejected by other scholars of evolution like Stephen Jay Gould and Richard Lewontin who argue that some features did not come into being to serve a specific purpose but were instead accidental byproducts of the evolutionary process. Those two authors gave the image of the spandrels in cathedrals.
In architecture, spandrels are a structural byproduct resulting from the placement a dome on top of four rounded arches. The spandrels fill in the empty space where the arch stops touching the top of the dome, stabilizing the overall structure. In finished cathedrals they are frequently painted and otherwise beautifully ornamented, as in the four famed spandrels of the Cathedral of San Marcos in Venice, Italy, that depict the four biblical rivers (Tigris, Euphrates, Indue, and Nile).
For Gould and Lewontin, if we adopt the adaptationist perspective, we might mistakenly assume the San Marcos spandrels were initially formed to be part of the cathedral’s artwork and miss their origin as necessary structural byproducts.
