Commercial Logic: It Makes For Bad Science

By L. ALfred James

You’re watching television. A commercial for a moisturizing lotion comes on. It shows a beautiful woman with perfect skin. Chances are a million to one that she did not get her perfect skin by using that exact product (in fact, she probably uses a ton of other products). But the skincare company is hoping you will not think about this.

Then another commercial comes on. This one shows a young man with a perfect physique using exercise equipment. Again, chances are a million to one that he didn’t get his perfect physique by using that exact kind of equipment (in fact, he probably has spent thousands of hours using many kinds of equipment). But the exercise equipment company is hoping you will not think about this.

Both of these companies are hoping you will assume that their products made these people beautiful.

They are hoping you will make these assumptions because they can’t come right out and explicitly make these claims. Why? Because they simply aren’t true. But they are strongly suggested. And these suggestions imply that you, the viewer, will also have great skin and a muscular body if you use the products.

Arguing with images: It is very convenient because companies don’t have to make explicit claims that might get them into trouble (for false advertising). “We never said you’d be hip and popular if you bought an Apple laptop.” “We never said you could play basketball like a superstar if you wear Nike shoes.” Maybe not. But these things are strongly suggested.

Believe it or not, this form of argumentation—arguing with images—is also the most common method used to convince people of evolution. It is very convenient because pictures say more than words, a lot more. And it makes it unnecessary to make any explicit claims that someone might challenge.

Among the most suggestive (and most persuasive) pictures are those that seem to demonstrate how ape-like creatures, over millions of years, became progressively more human-like. These pictures often have a sequence of fossil skulls, lined up in a sequence, starting from the most ancient to the most recent. The sequence suggests that there was some kind of ladder-like progression leading to humanity:

Just like the commercials we mentioned, these pictures are very suggestive. The periodic increase in size and changes in structure suggest that species A evolved into species B, and species B evolved into species C, and so on until humanity emerged. Indeed, the gradual increase in size is probably the most suggestive characteristic of these sequences. I’ve had many friends tell me about a series of skulls they saw in some small museum, or even in a magazine, sharing how deeply persuasive they found it. “As time passed, the species obviously got bigger brains, and they became more human-like.” Yup. It’s really suggestive, isn’t it?
But, if you think about it critically, this “progression” in size is not all that persuasive. After all, each individual skull represents an entire species, and most species are going to have numerous specimens of varying sizes. It is often the case (though not always) that specimens are chosen for display by a museum (or photographer), not because they accurately represent the “average size” of that species, but because they suggest “progress.”

The funny thing about these images is that most professional paleoanthropologists don’t actually believe in a ladder-like progression that led to humanity. As one of the more authoritative textbooks on the subject explains, “The fossil record of hominins [hominins are the human, and supposedly pre-human species], once notable for its ladder-like simplicity, is becoming increasingly bushy.”1 That is, when the fossils are arranged in a sequence (according to their best guess) it isn’t a linear sequence anymore. Instead, the fossils are arranged into groups that resemble nebulous “bushes” instead of “steps” on a ladder.

The only museums that still display a linear sequence of fossils are those that are out of touch with recent developments in paleoanthropology. Museums that are aware of the latest trends display a confusing hodgepodge of fossils grouped together by species (and grouped together by another category called a “genus”). For instance, here is a picture that I took myself at the Museum of Natural History in New York City. You’ll notice there is nothing like the linear progression that used to be implied.

And the fact that species of ancient primates can be grouped together is not at all shocking. We do the same today with most species of animal life. We group cats together (lions, tigers, domestic cats, etc.), and we also group dogs and dog-like species together (dogs, wolves, coyotes, jackals, etc.). Whatever you believe about the relationships between these species (whether it is a grouping of cat species, bird species, or any other animals) you can take the same approach to these species of hominins. Maybe you think cats are a “kind” and all other cats descended from them, or maybe you think they are all separate creations of a creator, or some other theory that you find plausible. Just know this: you can take that same approach to these hominins.

Speaking for myself, I think some of these separate hominin species should not actually be separated (for instance, I suspect that Homo ergaster and Homo erectus are really the same species). For most of the other species of hominins, I see them as being distinct and separate creations of God. I see no reason to think they emerged through evolution. Why do I think this way? Here is why: Just because hominin species might be similar in some parts of their anatomy, that is no reason to think that they must have a common ancestor or that they have an evolutionary relationship to each other. There are plenty of serious differences between them. And to only focus on the similarities is fallacious reasoning (called “cherry picking”).

The dotted lines that you see in this picture—the lines drawn between different species (and different groups)—form the branches of a theoretical “tree.” The technical term for this kind of tree is a “phylogeny.” But it is important to realize that it is entirely theoretical. It is simply a proposed evolutionary relationship. But recent research completely undermines these proposals (for details see the endnotes below).2

Moreover, it gets worse. Not only has science abandoned the idea of a ladder-like sequence leading up to human beings. For the past 50 years (actually, a little longer) many paleoanthropologists have also abandoned confidence in any proposed tree that is based primarily on similarities in the teeth, skull, or other bones. Listen to David Pilbeam, a world-renowned expert in paleoanthropology:

I am less sanguine than I used to be about the extent to which fossils can inform us about the sequence and timing of branching in [hominin] evolution,…I have become convinced that fossils by themselves can solve only parts of the puzzle, albeit important parts…You are much better off using molecular evidence if you want to be sure about the location and timing of branching points. And that is a difficult admission to have to make for someone who was brought up to believe that everything we needed to know about evolution could be got from the fossils.3

Please don’t miss this point: The most persuasive argument for human evolution has been these images in magazines, on television, and in museums. But this seemingly powerful argument has been shown to be utterly dubious. Those physical similarities do not indicate a common ancestor. There is thus no justifiable reason to conclude that these sequences of fossils (whether they are ladder-like or bush-like) tell us the truth about human origins.

So the next time you visit a museum you might see a display like this and think, “Wow, look at those skulls. That is really persuasive!” My advice: remember the commercials you see on TV. They use the same kind of logic: suggestive imagery.

This is not science. At best, this is propaganda. A more appropriate term would be false advertising. And if I could sue someone for it I would.

1. Roger Lewin and Robert A. Foley, Principles of Human Evolution (Malden, MA: Blackwell, 2004), 55.
2. Broadly speaking, the primary factor in proposing evolutionary relationships (phylogenies) between these extinct hominin species have been similarities in the shape and size of their craniums and similarities in the shape, position, and size of their teeth. (It’s actually a little more nuanced than that, and it involves very precise measurements and mathematics, but I’ll avoid getting technical.) Recently two scientists tested this method for determining evolutionary relationships. Here’s how they did it: They used this exact same method on human beings and species of primates that are alive and well today (chimpanzees, gorillas, baboons, etc.). They discovered that if they drew a tree (a phylogeny) based on this method—similarities in skulls and teeth—it flatly contradicted the tree that has already been drawn based on similarities in DNA. In their own word, “these results indicate that little confidence can be placed in phylogenies generated solely from higher primate craniodental evidence.” See Mark Collard and Bernard Wood, “How reliable are human phylogenetic hypotheses?” Proceedings of the National Academy of Sciences (USA), 97 (April 25, 2000): 5003–06.
3. Cited in Roger Lewin, Bones of Contention: Controversies in the Search for Human Origins (Chicago: The University of Chicago Press, 1987), 126; emphasis added.

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