EPS Article Library
The Design Inference from Specified Complexity Defended by Scholars Outside the Intelligent Design Movement - Page 4
Carl Sagan: Presidential Eggplants
and the "Face" on Mars
Carl Sagan was an American astronomer, astrobiologist, and science popularizer. Sagan was a pioneer in exobiology, promoting the Search for Extra-Terrestrial Intelligence (SETI). A famous author of popular science books, Sagan also wrote the novel Contact, upon which the 1997 film of the same name was based. Considering that the scientists in Contact infer the existence of extraterrestrials when they detect a radio signal exhibiting specified complexity, it is unsurprising that Sagan implicitly endorses CSI as a design detection criterion in his other writings.
In The Demon Haunted World, Sagan debunks a number of claims about purported instances of design. For example:
There was a celebrated eggplant that closely resembled Richard M. Nixon. What shall we deduce from this fact? Divine or extraterrestrial intervention? Republican meddling in eggplant genetics? No. We recognize that there are large numbers of eggplants in the world and that, given enough of them, sooner or later we'll come upon one that looks like a human face, even a very particular human face.
Notice that the suggestion of design here is based upon the fact that the eggplant in question exhibits a specification. In this case, the specification is looking like a human face, and more than that, looking like a particular human face (although it is hard to believe that the resemblance can have been all that tight). Sagan implicitly accepts that the eggplant exhibits a specification. So why does Sagan reject the idea that the correspondence between the eggplant and the Nixon specification is the result of design? Because the example lacks complexity. Given the number of human faces and eggplants that have existed, Sagan argues that it is not all that unlikely that we would come across an eggplant that bore a resemblance to Nixon. Hence we do not have to deduce divine, or extraterrestrial, or Republican design from the eggplant.
Sagan's argument for rejecting a design inference from the eggplant implicitly accepts that if the eggplant exhibited a specification at a sufficient level of complexity, then a design inference would be justified. In other words, Sagan recognized that a design inference is warranted when faced with an example of "specified complexity." This is why, in order to debunk a proposed instance of design which he admits exhibits specification, Sagan argues that the proposed example lacks sufficient complexity.
Sagan implicitly endorses the point that while specified complexity warrants an inference to "intelligent design," it does not in and of itself warrant an inference to any particular designer: "Divine or extraterrestrial intervention? Republican meddling in eggplant genetics?" All three explanations would be possible candidates if a design inference in this case were justified.
Sagan goes on to discuss the infamous so-called face on Mars, first photographed by one of the Viking orbiters in 1976. Sagan argues against a design inference in this instance by arguing that the "face" is neither very complex nor tightly specified. (Pointing out that something does not exhibit CSI can only justify the conclusion that it was not designed in concert with an application of Ockham's razor, since objects can be intelligently designed without exhibiting CSI. "Specified complexity" is only a positive test for design. Arguing against a design inference is not the same as arguing against design per se.) Sagan first examines the complexity of the "face":
Mars has a surface area of almost 150 million square kilometers. Is it so astonishing that one (comparatively) postage-stamp-sized patch in 150 million should look artificial-especially given our penchant, since infancy, for finding faces?
In other words, it is not all that unlikely that a small area of Mars should look sufficiently like a face under certain conditions to make it appear face-like to casual observation. Then Sagan goes after specification:
If we study the original image more carefully, we find that a strategically placed "nostril"-one that adds much to the impression of a face-is in fact a black dot corresponding to lost data in the radio transmission from Mars to Earth. The best picture of the Face shows one side lit by the Sun, the other in deep shadow. Using the original digital data, we can severely enhance the contrast in the shadows. When we do, we find something rather unfacelike there. The Face is at best half a face. . . . the Martian sphinx looks natural-not artificial, not a dead ringer for a human face.
While at first glance the "face" seems to exhibit a specification, a closer look shows that it does not. In Richard Dawkins' terminology, the supposed face on Mars is "designoid"; it gives a superficial impression of design at first glance, but the more we investigate its salient features, the less designed it looks. Hence Sagan concludes, "It was probably sculpted by slow geological processes over millions of years." The important point here is that in order to justify this conclusion Sagan seeks to undermine precisely those twin features that Dembski argues are as jointly sufficient conditions for justifying a design inference, namely, complexity and specification. If Sagan is right to argue that the "face" does not justify a design inference because it fails to exhibit specified complexity (indeed, because it is neither sufficiently complex nor tightly specified) then design theorists must be right to argue that anything which doesexhibit specified complexity should be attributed to intelligent design. For example, Sagan would not argue that slow geological processes sculpted the presidential faces on Mount Rushmore, because unlike the "face" on Mars, Mount Rushmore does exhibit specified complexity.
Although he does not use the terminology of "specified complexity," Sagan clearly endorses specified complexity as an adequate criterion of design detection, because he argues that design inferences cannot be supported if the putative designed object lacks sufficient complexity, fails to exhibit a specification, or both. This negative argument implies the positive argument that when a putative designed object does exhibit CSI, a design inference is thereby warranted.
Four Theists Outside the ID Movement
Keith Ward: Abiogenesis and Improbable Processes Structured to a Good End
Keith Ward is the Regius Professor of Divinity and head of the Faculty of Theology at the University of Oxford, and is a fellow of the British Academy. Ward contributed to the "Theistic Evolution" section of the Cambridge University volume Debating Design: From Darwin to DNA, which was coedited by Michael Ruse and William A. Dembski.
In God, Faith, and The New Millennium, Ward takes stock of the implications of the improbability of abiogenesis:
It seems hugely improbable that, in the primeval seas of the planet earth, amino acids should meet and combine to form large molecular structures capable of self-replication. . . . The motive for positing some sort of intelligent design is almost overwhelming.
Ward references a specification (being "capable of self-replication") and argues that the case for positing "intelligent design" is "almost overwhelming" because the structures exhibiting this specification are complex ("hugely improbable"). Ward goes on to argue that:
if one is asking . . . whether a very improbable process is compatible with intelligent design, the answer is that if the process is elegantly structured to a good end, then the more improbable the process, the more likely it is to be the product of intelligent design.
Ward is clearly not arguing for the mere compatibility of very improbable processes with intelligent design; rather, he is arguing that very improbable processes warrant explanation in terms of intelligent design when they are also specified.
Ward does (unnecessarily in my view) restrict what ID theorists would term a specification to the elegant achievement of a good end; but this is neither here nor there with respect to the observation that Ward argues for intelligent design by advancing the claim that nature exhibits non-ad hoc patterns at low probability and that the combination of the right sort of pattern (specifications) with sufficient improbability (complexity) warrants a design inference. That is, although Ward does not argue that his design inference is scientific, he is otherwise at least in the same ballpark as Dembski as regards the methodology of design detection.1 2 3 4 5 6