5. COSMIC DESIGN
6.4. The Importance of Philosophy for the Biological Debate
Whether the evolutionary origins of Behe’s examples of irreducible complexity remain a mystery or not, it seems that there are still unsolved mysteries within biology. It is not difficult to find acknowledgements of this in the discussion on Intelligent Design even from some critics of ID. For example, JohnJoe McFadden (an atheist professor of molecular genetics) explains one difficulty as follows:
The basic problem is that the complexity of biochemical pathways (unlike the eye) do not appear reducible. For instance, one of the cell’s essential biochemical is AMP (adenosine monophosphate), the precursor of ATP (the energy carrying molecule), which also finds its way into DNA, RNA and many other cellular components. AMP is made from ribose-5-phosphate, but the transformation involves thirteen independent steps involving twelve different enzymes. – – Each of the twelve enzymes involved in this pathway is absolutely essential for the biosynthesis of AMP. Darwinian evolution would require this complex system to have evolved from something simpler. But, unlike the eye, we cannot find the relics of simpler works. Half or a quarter or a twelfth of the pathway does not generate any AMP or indeed anything else of value to the cell. IT appears that the entire sequence of enzymes is needed to make any AMP. But without viable stepping stones, how can an entire complex system have evolved through Darwinian natural selection?754 Here McFadden’s idea is very similar to Behe’s argument from irreducible complexity succinctly: it is difficult to understand how the complex molecular system required for the production of AMP could have evolved, since the parts do not appear to have any use otherwise, and since AMP seems essential for life. McFadden argues that this presents a very difficult, even unsolvable problem for current conceptions of Darwinian evolution, and motivates transitioning into a new “quantum” understanding of evolution. Cellular biologist Franklin Harold similarly argues that “there are presently no detailed Darwinian accounts of the evolution of any biochemical or cellular system, only a variety of wishful speculations.” However,
“we should reject, as a matter of principle, the substitution of intelligent design for the dialogue of chance and necessity.“755
As I have argued, the literature does seem to contain at least some beginnings of accounts for biochemical evolution. However, Harold’s point is still interesting. Supposing that such detailed accounts are indeed missing at least to some degree, would we still have some other reasons for rejecting ID? Harold emphasizes the importance of philosophical principles rather than detailed evolutionary explanations in rejecting intelligent design.
Many defenders of evolutionary biology similarly present philosophical arguments against ID, though they also argue that there are scientific arguments for believing that the mysteries
754 McFadden 2000, 76. Quoted in Cunningham 2010, 277-278.
755 Harold 2001, 205.
of biology will be solved without ID. Previous successes in explaining complex systems like the eye should give us hope in also explaining presently unexplained complex structures.
Freeman and Herron also argue that appealing to design would be tantamount to invoking miracles, and this is unallowed in science.756
Though the estimates of proponents of ID and their critics differ on the severity of unsolved problems within evolutionary biology, both agree that evolutionary biology is still an incomplete science. Whereas critics of ID see waiting for naturalistic explanations of any problems as the most reasonable course, proponents of ID argue that the progress of science has only made the problems facing naturalistic theories worse. They want exact details of how the evolutionary transitions in questions could have happened before believing in the possibility of macroevolution through naturalistic mechanisms.757
The difference of opinion in the amount of unsolved problems and mysteries in evolutionary biology is significant for the philosophical interpretation of the remaining mysteries. There is a great deal of difference between the following three options: (1) over a hundred years of scientific work has only produced evidence against the possibility of macroevolution, not for it, (2) some ideas for explaining how macroevolution happens exist, but it is still mostly a mystery, and (3) every supposed mystery brought forward by skeptics of macroevolution has been thoroughly explained. Options 1 and 3 in particular make it possible to make an inductive prediction about the future direction of research. If all research so far has tended to refute the hypothesis of macroevolution by naturalistic mechanisms, then probably future research will also tend to refute this possibility. On the other hand, if all examples of mysteries and difficulties (like the origin of life or the origin of irreducible complexity) have been throughoutly explained by naturalistic evolutionary mechanisms, then probably future problems will be solved as well. This type of inductive argument does not guarantee the conclusion, but it does seem to offer a rational reason to believe in it.
If our own opinion of the matter falls somewhere between the extremes of the first and third option and comes closer to option 2, however, then it seems that the scientific arguments by themselves are not sufficient to determine what we should think about intelligent design. Though there is difference in whether things like irreducible complexity are seen as problems, an even more central difference would then seem to be the philosophical interpretation made of the incompleteness of evolutionary theory. The questions “should we reject intelligent design, even if natural explanations are incomplete”
and “what counts as evidence against Darwinism or intelligent design” are philosophical. It seems that not just scientific arguments, but also philosophical arguments are required to resist ID´s arguments.
756 Freeman & Herron 2007, 102.
757 Behe 2006a, chapters 10 & 11; Behe 2007; Axe 2012, 41-43. Critics could note that they do not require similar exact details about the nature and modus operandi of the designer before believing in intelligent design as the best explanation. ID’ers certainly seem to make more stringent demands of Darwinian explanation than of design.
Perhaps this could be justified by the difference of design-based explanations from mechanistic explanations. (See chapters 3.2. and 3.3.)
Typical philosophical critiques of ID’s biological design arguments are based on the varieties of methodological naturalism analysed in chapter 3.4. Some of the reasons are based on strong methodological naturalism and “in principle” arguments which aim to exclude all types of theistic or design-based explanation from science. Others are based on weak methodological naturalism and “in practice” arguments. In these types of arguments design is seen as a possible explanation of biology, which could in principle succeed in explaining biological order, but which does not in practice succeed in being a plausible explanation. For example, as seen in chapter 3.4, several evolutionary biologists argue that the design inference was completely reasonable a few centuries ago, but is only invalid today because Darwinian evolutionary biology provides a better explanation of the data.
Jerry Coyne’s defence of Darwinian evolutionary biology shows the way philosophical arguments are often used in the debate. Coyne, argues that we can be sure that mechanism of selection and mutation explains complex adaptations partly because the only alternative – creationism, including intelligent design – is so bad. Coyne’s arguments are that (1) ID is unscientific, because it is untestable, (2) ID is a “God of the gaps” -argument, (3) ID can explain potentially any feature of nature, and thus explains nothing, and (4) the burden of proof is not on naturalists to provide a step-by-step demonstration of how complex systems can evolve, but rather on critics who should demonstrate that the step-by-step evolution of some complex system is impossible. Coyne’s case does not rest only on these philosophical arguments, because he goes on to explain empirical evidence for the evolution of complex adaptations (using the evidences from homology and the evolution of the eye, for example).758 Nevertheless, Coyne’s philosophical arguments certainly seem to affect the level of certainty he has regarding natural selection as the mechanism of evolution. My point is not that it is illegitimate to use such philosophical arguments (as long as they are good arguments), but simply that their importance for the debate between ID and naturalism should be recognized.
Must Evolutionary Biology and Design be Opposed?
In chapter 6, I have focused on the debate between ID and naturalistic evolution. In this debate, design and naturalistic evolution are seen as two competing explanations of the same data. However, it is important to note that this is not the only way to understand the relationship between evolution and design. As theistic evolutionists argue, evolution and design could be compatible. Theistic evolutionist can still accept cosmic design arguments, even if there is a conflict between design and evolution as explanations on the biological level. However, I wonder if theistic evolutionists could also get some use out of ID’s critique of naturalistic evolution.
758 Coyne 2009, 136-143.
Consider Behe’s argument from irreducible complexity. Behe argues that it is unlikely that proteins which are specialized for one function just happen to be easily convertible to serve in another role, and that the evolution of irreducible complexity truly can proceed without multiple simultaneous mutations. For Behe, this just seems too serendipitous and incredible to be true. But suppose that such evolutionary pathways nevertheless exist. A theistic evolutionist could argue that this just goes to show how strict the conditions for evolvability are, and how much fine-tuning evolution allows. In a universe designed to allow for evolution, perhaps such serendipity could be expected, rather than being unlikely. Thus a theistic evolutionist who believes both in mainstream evolutionary theory and in the designedness of the cosmos could argue that Behe’s argument simply reveals the extent of fine-tuning required by evolution, rather than refuting evolution. This is a philosophical and theological point, of course – the existence of such pathways is an empirical question. My point is merely that that this may be a possible strategy for a defender of the cosmic design argument to get some use out of Behe’s argument, even if Darwinian evolution is accepted as a valid explanation for biological complexity. ID theorist Ann Gauger notes the same point when discussing the fitness landscape required for protein evolution: “So unless someone paved a highway to Mt. Whitney that went uphill every step of the way, Darwin’s engine would never get out of Death Valley. But a paved highway isn’t evolution, it’s design.”759 I will come return to these ideas on the compatibility of design and Darwinism in chapter 8.
The present chapter has brought two important questions to the surface. First, how should we react to (naturalistically) unexplained mysteries in nature? Second, how should we understand the relationship between natural explanations and belief in the designedness of nature? Both of these questions are related to another common philosophical and theological critique of ID: understanding it as a “God of the gaps”-arguments. I now turn to this topic.
759 Gauger 2013. A recent study at the University of Helsinki also notes that natural selection works in some types of fitness maps, but not others. See Salazar-Ciudad & Marin-Riera 2013. The evolution of “evolvable” organisms must be possible. (Sansom 2008).