The core of what is known as ‘intelligent design’ is an inference that, when interpreted charitably, can be construed as something along these lines:
Design Inference (DI):
There are certain facts about biology, and especially genetics, such that it is reasonable to infer from these facts that an intelligent agent is at least partly responsible for the diversity of life on earth.
Taken alone, this shouldn’t be too objectionable to scientists, at least at first glance. Scientists infer that things were designed fairly often – arrowheads, stone tools, etc. But of course, this isn’t a complete picture; the scientist’s job is never as simple as this. To see how, consider the design inference in the case of an arrowhead in more detail:
Imagine that you are walking along in the plains of North America, and you stumble across a stone object half-buried in the sand. Upon digging it out, you see that it’s made of stone, triangular, and has crudely sharpened edges. Given this, you conclude that it was almost certainly designed by some kind of intelligent agent. And you’d be reasonable to do so; because while it *could* have been fashioned by some natural process, you’re not aware of any that could actually do so. On the other hand, you can think of several ways in which intelligent agents could rather easily fashion such an object.
But you’re not satisfied yet. You’re a curious person; you want to know what kind of intelligent agent would make such a device, and furthermore, for what purpose. So to get things started, you rush back home and list as many potential designers as you can think of:
1. pre-U.S. native americans
3. modern-day humans
4. ancient egyptians
5. a perfect, supernatural, arrowhead deity
To begin narrowing things down, you first examine the object in greater detail. You look at it under a magnifying glass, and see that it’s been fashioned rather crudely, likely with primitive tools. You also notice that it’s made out of granite. With these facts in mind, you consider what sort of arrowhead design you’d expect to see given each of the potential explanations above:
1. triangular, made of granite, built with primitive tools, found in North America
2. made of some advanced metal, built with advanced technology
3. made of carbon steel, built with modern tools, razor sharp, three-bladed
4. made of granite, built with primitive tools, found in Africa
5. made of the best possible substance for making arrowheads, designed perfectly, completely unlike anything humans have made
Next, you consider why each of these potential designers would be motivated to construct an arrowhead:
1. to hunt game, or to shoot at targets
2. no reason apparent. surely, aliens would have more effective methods and devices
3. to hunt game, or to shoot at targets
4. to hunt game, or to shoot at targets
5. as a gift to its followers, so they could hunt game, or shoot at targets
From this analysis, we can conclude that probably (in fact, almost certainly), the best explanation for the arrowhead is that it was designed by pre-U.S. native americans. They had a good reason to construct arrowheads, *and* this arrowhead is the kind of arrowhead we’d expect, *and* it was found in the location we’d expect, if pre-U.S. native americans were the designers. In contrast, none of the other potential designers fit as well with the specifics.
Now, let’s move on to looking at design in nature. For the sake of argument, I’m going to grant the design inference at the beginning of this post, and look at which sort of designer is the best explanation of said design. Here are some options:
4. time travelers (causal loop)
5. non-God supernatural being
As in the case of the arrowhead, we shouldn’t just stop at concluding “some sort of designer”. Explanations, if they are to be good explanations, need to be more robust than that. So, like the arrowhead, let’s examine the details of the designed ‘object’ – human bodies.
So what relevant features can we point out about human bodies? Well first off, they’re physical. They have a lifespan of roughly 80 years. They’re extremely vulnerable to being damaged by temperature or by physical trauma. They’re not very efficient.
Given 1, 2, and 4, we’d probably expect these things (or similar things) to be the case. Extraterrestrials would have to work with physical matter, and aren’t perfect. Given that we’re a simulation constructed by some other sort of physical being, we might expect such beings to roughly model what they’re familiar with in the simulation. And given a causal loop where a human time traveler goes back and designs life in order to “complete the loop” of his own existence, it’s *exactly* what we’d expect.
5 is a toss-up. A non-God supernatural being may or may not still have internal or external limitations that necessitate working with physical matter. But with 3, God, there are no such limitations. While it’s true that given God, we’d expect to see minds that are capable of being moral agents, physical bodies that are inefficient and easily damaged seem not only superfluous, but contrary to what we’d expect such a being to design.
So, absent some reason to think that God would want to create inefficient physical bodies that are easily damaged, intelligent design advocates should not be silent on the identity of the designer. Rather, they should reject God as said designer. But this is a large bullet to bite for the theistic I.D. advocate, as it entails that God did not create the universe with humans in mind. Thus, the design inference, if it is a rational inference to make, is evidence against theism.