In the first half of Darwin and Design, Michael Ruse presents the history of Western thought concerning the argument from design and the use of teleological language in the sciences beginning with the ancient Greeks and progressing through Darwinism. He explains how philosophy, theology and socioeconomic ideas often had greater influence than natural evidence on what the various figures that lived and studied during that period of history were willing to accept or reject concerning teleology. For example, he describes how, after the scientific revolution, the belief in a miraculous creation began to erode, in part because of discoveries such as the phenomenon of animal extinction, but much more because of emerging philosophical and socioeconomic ideas that were discordant with traditional Christianity. Ruse says, “Above all, the crucial factor was a growing enthusiasm in the eighteenth century for the philosophy of progress—the belief that we humans through unaided effort can improve our knowledge and, through science and technology, our lot in life” (54). It wasn’t difficult to translate these ideas into views about the biological world and then to consider evolution of living things a confirmation of the appropriateness of progress in human society.
Despite being an agnostic and committed evolutionist, Ruse employs, presumably as a rhetorical aid, a rather gracious tone when speaking of the various theologies held by key thinkers throughout this period. However, he repeatedly stresses the need (he perceives) for mutually exclusive science and religion. For example he says, “There was the worrying mix of science and theology. The argument to design gave an answer to the question set by the argument to complexity, but it was not a scientific answer—and that increasingly was becoming a problem” (87). The irony of Ruse’s position is that Darwin himself wasn’t keeping the two completely separate; there was in fact a theological naturalism pervading Origin; his was a “greater God” theology. He made major presumptions about the nature of divine creation and never considered the Christian doctrine of the fall, with its possible ramifications, as a possible theodicy. Ruse says, “In fact, as soon as he became an evolutionist, Darwin was looking at useless features as confirmation of his theory and evidence to be used against a direct creationist position. He would expect rough edges, whereas a miracle-monger would not” (113).
Ruse goes on to discuss two of Darwin’s most ardent supporters (contemporaries), T.H. Huxley and Asa Gray. These two men were vastly different in their motivation for embracing Darwinism, a fact that further supports the aforementioned thesis that factors outside of science had great influence on how evolution was handled. Huxley, a fierce proponent of science education used evolution more as a political tool to promote his ideas about establishing a new social order contrary to the Church of England (which symbolized forces opposed to change). Ruse says, “Huxley and his friends needed a new ideology for a new age—they needed their own religion or religion-equivalent to offer the public… It became a kind of secular religion…Progress rather thanProvidence” (134, 135). Gray viewed evolution from a completely different angle. A devout Christian, Gray saw a harmony between Darwinism and natural theology; he didn’t consider an evolutionary origin of species a threat to the idea of an intelligent First Cause. In fact, he thought it benefited the argument to design by eliminating the need for divine explanation of perceived imperfection or inefficiency in nature. It’s interesting to note that Gray was the one to appreciate adaptation in contrast to Huxley’s indifference to it.
Throughout the second half of Darwin and Design, Ruse acknowledges the pervasive use of design language in evolutionary biology and attempts to make a case for the mere “appearance of design” as opposed to “actual design” in the complexity of life. He boldly states, “Under the forces of natural selection working on nondirected variations, complex structures… can indeed evolve and have in fact evolved many times” (Ruse, 255). To support his argument, he uses meagerly supported (or entirely unsupported) conjecture about how complex traits could have been naturally formed through a blind process lacking a predetermined goal. For example, in his rebuttal of Behe’s irreducible complexity, he tells a very Darwin-style “just-so” story involving the use of a supporting structure that allows the construction of an arched bridge, stone by stone. He says, “Likewise, one can imagine a biochemical sequential process with several stages, on parts of which other processes piggyback, as it were” (Ruse, 320). He uses the Krebs cycle as an example, declaring with confidence that “Each part of the cycle started life doing something else and then…was grabbed by the cells and put to a new use” (Ruse, 321).Ruse believes this is a rebuttal to the concept of irreducible complexity, when all he has really done is point out that each sub-process in the cycle has its own task. Obviously, the Krebs cycle is not an irreducibly complex system; Ruse is using a straw man argument. (For an excellent article on the continuing strength of the Behean argument, click here.)
A major tenet of Ruse’s argument for naturally-arising complexity seems to be that not all mutations are beneficial by themselves, but that over time neutral mutations could accumulate into complex systems that do impart adaptational advantage to the organism. He makes no attempt to explain how so many mutations could be continually conserved by the organism, remaining immune to natural selection, until they add up to produce a benefit. Ironically, he criticizes Behe for supposing that preformed genes could be preserved for long periods of time, saying that because unexpressed genes would not be acted on by natural selection, they would be corrupted over time and become useless. So, when it suits Ruse to have an organism’s genotype preserve something for later use, all is well; but if someone else wants to claim the preservation of something pre-designed,Rusethinks it ridiculous.
Ruse draws a distinction between “design thinking” and “adaptation thinking.” For example, he describes the progress of scientific thought concerning the function of the bony plates that ran down the length of the stegosaurus, and what that purpose says about the physiology of the animal and the environment in which it lived. Based on the structure and evidence of their likely arrangement, it is assumed that the plates functioned in temperature regulation. Ruse says, “Paleontologists feel that they now have a handle on one of the biggest and most interesting questions in their trade. A triumph of adaptationist thinking” (Ruse, 188). The question one could ask in response is: couldn’t the exact same conclusions about the plates’ beneficial function be reached by someone assuming actual design? After all, design is purposeful, blind evolution is not. However, true to the fashion of evolutionary thinking, Ruse harnesses observations from anatomy and physiology as support for his argument by subjecting them to an evolutionary interpretation.