Our starting point must be ordinary language. As David Stove points out, "it is a fact about the meaning of a common English word, that you cannot say that something was designed, without implying that it was intended; any more than you can say that a person was divorced, without implying that he or she was previously married." (Darwinian Fairytales, p. 190, emphasis added.) In other words, it is an analytic proposition that a designed object is one that was intended in the same way that it is an analytic proposition that a divorced person is one who was previously married. These are two conceptual truths, and anyone who uses designed object and divorced person in a way counter to these truths either does not understand these concepts or else has some serious explaining to do.
We can put aside for the moment that biologists have actually written multiple volumes to do this serious explaining. Perhaps this work is not serious enough for Dr. Vallicella, as most of the work is written for the popular audience. The first step, I think, is to acknowledge that no individual book, no matter how well or carefully written, would suffice to introduce an entirely new vocabulary, one that has no real equivalences into English, as a part of a discussion on a topic that already requires years of post-graduate study and work to understand, and result in something that a person with high-school education, or even a degree in philosophy, will understand. Scientists spend years learning to adjust and adapt their understanding of the English words, any new vocabulary would merely occupy an academic niche that has no need for it.
1. Mayr tells us in the chapter on Natural Selection that "Every species produces vastly more offspring than can survive from generation to generation." (117) Sorry to be such a quibbler, but is this true? 'Every' includes homo s. Does our kind produce vastly more offpsring than can survive from generation to generation?
Yes, we do. This restraint has been lifted in the last 10,000 years or so since the discovery of agriculture, and in that time our population has grown exponentially (which is the alternative when a species is temporarily unable to fill its niche). However, we will at some point exceed the ability of our environment to support our numbers. China is already experiencing a version of this issue, hence their official policy of couple being allowed one child. Eventually every culture will be facing this issue.
Then we read: "All the individuals of a population differ genetically from each other. They are exposed to the adversity of the environment, and almost all of them perish or fail to reproduce." (117) Really? Almost all of the members of our species perish or fail to reproduce?
Again, this was historically true. In pre-industrial times, it was commonplace to lose more children before puberty have children reach puberty.
Quoting Mayr, with interspersed comments, he says:
Selection is not teleological (goal-directed). Indeed, how could an elimination process be teleological? [It can't be, my man!] Selection does not have a long-term goal. [Or a short-term one either!]
This seems to be odd position. As was pointed out twice in the comments, there are several ways to design by elimination.
The following three positions need to be distinguished:
1. There is design in nature, and a complete account of it is impossible without recourse to a cosmic designer such as God.
2. There is intrinsic design in nature, and it is wholly explainable in naturalistic terms.
3. There is no intrinsic design in nature: all features that exhibit design, purpose, function are observer-relative, and the only observers are themselves denizens of the natural world.
Theists who rely on design arguments subscribe to (1), while some naturalist philosophers come out in favor of (2). (2), however, involves the claim that there is intrinsic design in nature, a claim that is far from obvious, and is arguably inconsistent with Darwinism.
So it looks as if (3) is the correct view. The following considerations will be based on passages from John Searle's The Construction of Social Reality (The Free Press, 1995). We consider the case for the contention that there are no intrinsic design features in nature, equivalently, that biological functions are observer-relative.
Again, we see an example of a trilemma, one that is played subtlety and much more carefully than the ham-fisted approach outlined by Cothran. The very first question I would have regarding these is why the designer must be cosmic and singular, as opposed to highly limited and plural. The other is the restriction of purpose to designers and other external agents.
2. Searle's point about functions is that they are never intrinsic but always observer-relative. Functions are assigned or imposed by us. A burro (my example) is not intrinsically a beast of burden but is susceptible to having that functional role imposed on it. Or else we fabricate a mechanical 'burro' to suit our purposes. Similarly, cats and dogs are not pets intrinsically: the pet role is imposed by us.
There are no functions in the natural world: "nature knows nothing of functions." (14). Hearts occur in nature, and it is an observer-independent fact that they cause blood to course through the bodies that house them. But the function of the heart to pump blood is not intrinsic to nature.
This is a very human-centric position. Does a bird, or even an ant, assign a function to it's own heart? You can make arguments about degrees of consciousness, but I don't think anyone understands consciousness well enough to give a precise degree as to the level needed to say something has a function. Remove the ant's heart, and it is dead. I don't know as much about intention, consciousness, or the philosophical discussions thereof to claim any sort of expertise, but I know enough to be fairly sure that there is no universal position on whether an ant can assign purpose, on some level, to its own survival, and by extension its own heart.
So although one does discover how the heart works -- its mechanism -- one does not discover any teleology. Searle:It is because we take it for granted in biology that life and survival are values that we can discover that the function of the heart is to pump blood. If we thought that the most important value in the world was to glorify God by making thumping noises, then the function of the heart would be to make a thumping noise, and the noisier heart would be the better heart.
To the organisms involved, survival is a value, at least in the sense that their reactions to stimuli are those that developed to ensure survival. The language confusion here, to the degree it exists at all, is quite small.
4. Compare airplane wings and eagles' wings. The wings of an airplane are designed by human engineers for a purpose: to generate lift so that a heavier-than-air craft can become airborne. They are for flying. Now it might seem that the same is true of eagle's wings: they too are for flying. This is true, but only relative to us. Because we value mobility and survival, we project onto the eagles' wings the function of being for flying and escaping predators. Searle's point, however, is that nothing in nature intrinsically has a function. He is not saying that airplane wings have a purpose while eagles' wings don't: they both have a purpose, but it is observer-relative. In a world without beings like us, bird's wings and birds' nests would exist and have causes and effects but lack functions.
The eagle will likely interpret this differently.