In the previous posting I described a popular IDC argument that things like watches and Mount Rushmore are obviously ‘designed’ objects and thus imply the existence of a designer. By analogy, it is asserted that certain biological systems are also supposed to bear the hallmarks of design and thus must require a designer (aka god) too.

This argument seems to be persuasive to many people because I repeatedly hear it various forms. The usual response to it by scientists is to argue that the appearance of biological design is only an illusion and that random mutation and natural selection are perfectly capable of producing the seemingly complex biological forms that seem to stymie the IDC people.

But there is a philosophical issue here as well and that is what I want to address. First of all, while we all supposedly can agree that a watch and Mount Rushmore could not have simply appeared without human action, how is it that we are so sure that this is the case that we can accede to it without argument? How is it that in these cases we can definitely identify them as designed objects and say that other things (like rocks) are not designed?

Identifying the methods we use to classify things is an old and important question that has been addressed by many philosophers, most notably Ludwig Wittgenstein. To illustrate how Wittgenstein differed from his predecessors, I will quote Thomas Kuhn’s The Structure of Scientific Revolutions (pages 44-45):

What need we know, Wittgenstein asked, in order that we can apply terms like ‘chair,’ or ‘leaf,’ or ‘game’ unequivocally and without provoking argument?

That question is very old and has generally been answered by saying that we must know, consciously or intuitively, what a chair, or a leaf, or a game is. We must, that is, grasp some set of attributes that all games and that only games have in common. Wittgenstein, however, concluded that, given the way we use language and the sort of world to which we apply it, there need be no such set of characteristics. Though a discussion of some of the attributes shared by a number of games or chairs or leaves often helps us learn how to employ the corresponding term, there is no set of characteristics that is simultaneously applicable to all members of a class and to them alone. [Note: This is essentially the demarcation problem dealing with the difficulty of requiring necessary and sufficient conditions that was discussed in an earlier posting – MS] Instead, confronted with a previously unobserved activity, we apply the term ‘game’ because what we are seeing bears a close “family resemblance” to a number of the activities that we have previously learned to call by that name. For Wittgenstein, in short, games, and chairs, and leaves are natural families, each constituted by a network of overlapping and crisscross resemblances. (emphasis in original)

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We can recognize objects designed by humans because we have seen multiple examples of things designed by humans and we can recognize the differences between them and those found ‘in nature’ (and thus not designed by humans) like rocks, grass, rivers, etc.. The reason why we can all so easily agree that watches are designed is that they have a family resemblance to other items (cars, trains, aeroplanes, iPods, etc.) that we know were definitely designed by humans. Similarly with Rushmore, we have seen numerous examples of sculptures and other art definitely designed by humans and so we can recognize the family resemblance of Rushmore to them.

Small children very quickly can learn to identify, purely on the basis of such family resemblances, whether the animal they see in a field is a horse or a cow even though they may not be able to precisely define each animal. This happens after they have seen some horses and cows and been told by their parents which is which. Even parents don’t try to define the animals. They just tell children which is which and that seems to be sufficient.

But when we use this as an analogy, as IDC advocates do, to identifying items (like Behe’s bacterial flagellum) as being designed by god, we run into a problem. In order to make that kind of family resemblance identification, we have to already know for sure many examples of things that have been designed by god and those that have not. But how can we know this? Of all the things that we see around us, what examples do we have of things that we definitely know have been designed by god and those that have not? That might be hard to get consensus on.

If you believe in a god who designed everything (grains of sand, rocks, Rush Limbaugh), then the classification system breaks down. If you believe in a god who designed only some things and let others come about ‘naturally’, then you get caught in a vicious cycle where the things you simply believe to be designed are then used again as models for identifying design of other things.

How, for example, would we teach children how to distinguish between things that are designed by god and those that are not, like we do with horses and cows? What are the things we could point to as exemplars of those two categories? While each of us has a personal experiential database that we can draw upon and use to identify family resemblances between human-designed objects and non-human designed objects, we do not have corresponding databases of god-designed and non-god designed objects.

Thus the watch/Rushmore analogy argument for design does not work in identifying the existence of god as a designer, unless we have an independent means of knowing which items were definitely designed by god and which were not, so that we can classify any specific item according to the family resemblance to each group.