Wither the Design Argument?
Wallace I. Matson considers the following two arguments equally weak:
I. Natural objects share with artifacts the common characteristics of adjustment of parts and curious adapting of means to ends.
II. Artifacts have these characteristics because they are products of design.
Conclusion. Therefore natural objects are probably products of a great designer.
and
I’. Natural objects share with artifacts the common characteristics of being colored.
II’. Artifacts are colored by being painted or dyed.
Conclusion’. Therefore natural objects are probably colored by a great painter-dyer. (Critiques of God, 84ff)
But of course they are in no way equivalent. For we do not infer that an object is intelligently designed from its being colored. But we can so infer this from its having adjustment of parts and curious adapting of means to ends. In other words, it is true that everything that exhibits curious adaptation of means to ends and is such that we know whether or not it was the product of intelligent design, in fact was the product of intelligent design. But it is not true that everything that is colored and is such that we know whether or not it was the product of intelligent design, in fact was the product of intelligent design.
Our author, of course, disagrees: “Proponents of the design argument take it for granted that the properties according to which we judge whether or not some object is an artifact are accurate adjustment of parts and curious adapting of means to ends. But that is not the way we judge, even provisionally, whether something is an artifact or not. This is clear from our being able to tell whether something is an artifact without knowing what it is for or whether its parts are accurately adjusted.” (88) But of course, these criteria are sufficient for correct identification of intelligently designed objects; they need not be necessary, as well. For example, specified complexity is another general algorithm for inferring design which does not reference means and ends. As I point out here, purpose of design is a different measure than complexity of design. And irreducible complexity is a mark of design which is specifically aimed at countering the possibility of undirected Darwinian evolution of biological structures.
Purpose of design, however, is linked to complexity, and complexity, to purpose. For specified complexity requires “conditionally independent patterns.” As Dembski writes,
Crucial here is that patterns not be artificially imposed on events after the fact. For instance, if an archer shoots arrows at a wall and we then paint targets around the arrows so that they stick squarely in the bull’s-eyes, we impose a pattern after the fact. Any such pattern is not independent of the arrow’s trajectory. On the other hand, if the targets are set up in advance (”specified”) and then the archer hits them accurately, we know it was not by chance but rather by design (provided, of course, that hitting the targets is sufficiently improbable). The way to characterize this independence of patterns is via the probabilistic notion of conditional independence. A pattern is conditionally independent of an event if adding our knowledge of the pattern to a chance hypothesis does not alter the event’s probability under that hypothesis. (The Design Revolution, 82)
And the purpose of design is one such independent pattern. For example, getting a royal flush in poker is the specification of an event, precisely because there is a purpose to getting it, namely winning the game. Victory in poker is an example of a pattern which is indeed not imposed after the fact but is “conditionally independent.” Or, a biological system is specified, because it is essential for the organism to survive and prosper, also a clear purpose (for the organism).
On the other hand, specified complexity ministers to purpose. As I write elsewhere,
What’s more, “In order to be a candidate for natural selection a system must have minimal function: the ability to accomplish a task in physically realistic circumstances.” (Behe, Darwin’s Black Box, 45) This is an additional requirement to IC, which merely lists the parts that are jointly necessary for any function, even that below minimal. Minimal function demands that, even if all the parts are present, they be such as to 1. enable the molecular machine to do its job with at least minimal competence; 2. make the machine be not less efficient than can be achieved with simpler means. The proper function is one that requires “the greatest amount of the system’s internal complexity. … The function of a system is determined from the system’s internal logic: the function is not necessarily the same thing as the purpose to which the designer wished to apply the system.” (Behe, 196)
But, we might say, any machine worth building is inevitably going to be complex, even irreducibly complex. Thus, if a system (such as a computer or the immune system) is to fulfill its function, its specified complexity must needs be very high.