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Can You Mix Engineering and Natural Selection?


A strange brew of terminology appears in some studies on Darwinian evolution: the idea that natural selection follows engineering principles. The scientists involved usually have no intention of mixing natural selection with intelligent design; they just assume that natural selection will lead to well-engineered results.

Is Natural Selection Up to Bat?

Here's a good example in a news item from UMass Amherst, "Using Engineering Plus Evolutionary Analyses to Answer Natural Selection Questions in Bats and Other Species." (Emphasis added.)

Introducing a new approach that combines evolutionary and engineering analyses to identify the targets of natural selection, researchers report in the current issue of Evolution that the new tool opens a way of discovering evidence for selection for biomechanical function in very diverse organisms and of reconstructing skull shapes in long-extinct ancestral species.

Sounds interesting. How does it work? First, assume evolution: "Natural selection is the driving force behind adaptation to new niches," they assert. "[B]ut it can be difficult to identify which features are the targets of selection." In other words, what is the hidden hand of natural selection aiming at?

Off they went, analyzing bat snouts. They looked at snouts of two hundred species of leaf-nosed bats, comparing their diet with the length and breadth of the snout and palate. A "very cool new thing" about their work was to apply engineering to Darwin's tree: "The engineering model allowed us to identify the biomechanical functions that natural selection worked on."

[Elizabeth Dumont] and colleagues built an engineering model of a bat skull that can morph into the shape of any species, and used it to create skulls with all possible combinations of snout length and width. Then they ran engineering analyses on all the models to assess their structural strength and mechanical advantage, a measure of how efficiently and how hard bats can bite.

The team found three optima of mechanical advantage the bat snouts clustered around. Not surprisingly, these optima corresponded to the kind of food they ate. Need to reach deep into a flower? Your snout will be long and narrow, but lack a strong bite. Need to bite into hard figs? Your snout will be short, with a wide palate that can pack a strong bite. "Thanks to this new approach," Dumont says, "we were able to answer our original question about natural selection in the evolution of these bats."

Is an aimless, unguided natural process really capable of optimizing mechanical advantage?

For one thing, before the said "adaptive radiation" of these bats occurred (which is not controversial, even to creationists), the ancestral bats already possessed snouts, teeth, palates, and digestive tracts. Their snouts were already optimized for mechanical advantage. As far as we know from fossil record, they also possessed the ability to fly. They had senses for detecting food, navigating the habitat, and bearing offspring passing on these traits. The problem for the Darwinist is accounting for the origin of these integrated systems of complex, interrelated functional wholes -- not for explaining minor tweaks to parts that already existed.

More importantly, the authors overlook the more logical inference that the engineering capable of adapting was designed in the bats. Engineers, for instance, eagerly seek to devise robots that can adapt to new environments. It's not the environment that is the "driving force behind adaptation," but rather the engineering skill of the designer to deal with novel circumstances. Picture a helicopter drone facing an obstacle like a mountain. What robot designer would appreciate it if a reporter said that a mountain was the "driving force behind" the flying robot's ability to see it and fly over it? That's what the evolutionists did here; they shifted the engineering to the environment, which is blind and careless about what drones or bats want to do.

Tigers and Trees: Natural Law and Natural Selection

A more subtle example of misdirection appears in a report from the University of Maryland, "How Evolution Shapes the Geometries of Life." Here's the question to be answered by evolution:

Why does a mouse's heart beat about the same number of times in its lifetime as an elephant's, although the mouse lives about a year, while an elephant sees 70 winters come and go? Why do small plants and animals mature faster than large ones? Why has nature chosen such radically different forms as the loose-limbed beauty of a flowering tree and the fearful symmetry of a tiger?

These questions have puzzled life scientists since ancient times.

A team of scientists invoked Kleiber's Law (a rare case of a mathematical formula in biology) to link shapes of living things with their metabolism, allowing them to find "mathematical and physical principles" that can explain why giant sequoias are tall, tigers are sleek, and mice are high-strung and short-lived. Kleiber's Law, formulated by Max Kleiber in 1930, says that metabolism equals mass to the 3/4 power.

Picture two organisms: a tree and a tiger. In evolutionary terms, the tree has the easier task: convert sunlight to energy and move it within a body that more or less stays put. To make that task as efficient as possible, the tree has evolved a branching shape with many surfaces -- its leaves.

The tiger, by contrast, needs to get rid of excess heat from burning meat. When you compare surface area to metabolism, you find that Kleiber's Law fits observations of many things about plants and animals -- even their life spans and clutch size.

It doesn't, though, explain why the relation holds.

The researchers had two goals. First, they wanted to explain the 3/4-power term for animals, since one might expect the relationship to follow that of surface area and volume -- a 2/3-power formula. The answer appears to be the extra energy needed direct energy flow and heat dissipation by means of a circulatory system. "Plugging that information into their equation, the researchers found they had attained a complete explanation for Kleiber's Law."

So far so good. The second goal was to explain how plants and animals arrived at the same geometric solution:

"An elegant answer sometimes is the right one, and there's an elegance to this in the sense that it uses very simple geometric arguments," said physicist Amos Maritan of the University of Padua. "It doesn't call for any specialized structures. It has very few preconditions. You have these two lineages, plants and animals, that are very different and they arrive at the same conclusion. That is what's called convergent evolution, and the stunning result is that it's being driven by the underlying physics and the underlying math."

The news sounds like a celebration. The university's evolutionary experts solved a long-standing puzzle. But did they?

Again, note the misdirection. We are told that the plants and animals "arrive at" a "conclusion" by means of "convergent evolution." The "underlying physics and the underlying math" are somehow driving this result. "It [Kleiber's Law] doesn't call for any specialized structures," they say. But a tiger does! A tiger needs a heart, a digestive system, and much more. A tree needs photosynthesis and active transport. Will these things "arrive" just because a mathematical formula dictates a geometric relationship must hold?


The evolutionary "explanation" resembles the old Aristotelian way of explaining the world (e.g., a rock falls because that is its "nature"). Tigers evolve hearts because a geometric formula "drives" them to produce one. Trees develop a branching structure because Kleiber's Law drives them to relate their surface area to their mass. Food sources drive bats to adapt their snouts to provide an optimum mechanical advantage. It's in the "nature" of environments and mathematical laws to produce these things.

How does this improve on magic? We might as well think that the environment says "Abracadabra!" and a circulatory system appears. We might as well write a formula on a whiteboard and watch trees grow. Evolutionists have essentially transformed a magic wand into a personified figure of Nature or Math, giving it the power to conjure up complex systems on cue. The emptiness of this kind of explanation should be apparent on a little reflection. All they have done is displace the engineering skill onto a mindless entity, treating it like a designer.

Our experience with software and robotics shows us, by contrast, that complex systems can be engineered for adaptation and robustness. Similarly, our experience shows us that unguided processes lead to breakdowns of function. Our experience transfers naturally to our observations of living organisms, allowing us to infer design when we see it.

Darwinians try to portray intelligent design as some kind of "magic," but the shoe goes on the other foot. There's nothing magical about design. We use it all the time. We know how to design things, and we recognize others' designs. Universally, complex functional systems originate by the planning of an intelligent cause, able to conceive a distant target, then able to create and integrate functional parts to reach it. On this point, beware of misdirection.

Photo: Artibeus sp. in Tortuguero Nationalpark, Costa Rica/Wikipedia.