Excavating Hidden Truths

Three weeks ago I woke up in a world that took newfound interest in the accuracy of dinosaur reconstructions.

From Vinther,  et al  (2016). Sculptor:  Bob Nicholls .

From Vinther, et al (2016). Sculptor: Bob Nicholls.

(I had gone to bed the previous evening in a world wherein companies still produced three-fingered T. rex toys; imagine my surprise.)

The Psittacosaurus reconstruction pictured above is the outcome of combined good luck and hard work. Frankfurt's Senkenberg Museum houses an extraordinary Psittacosaurus specimen that preserves not only imprints of the animal's feathery integument, but also evidence of its soft tissues and skin pigments. A research team led by the University of Bristol's Jakob Vinther and paleoartist Bob Nicholls studied every micrometer of the Senkenberg specimen, mapping out its body outline and the distribution of different-colored skin cells. Only with this one-of-a-kind bounty of fossil information could the team produce the "most accurate depiction of a dinosaur ever created."

The Senkenberg  Psittacosaurus  specimen (top) and a color-coded map of the specimen's skin, pigment cells, and bones (Vinther,  et al  2016).

The Senkenberg Psittacosaurus specimen (top) and a color-coded map of the specimen's skin, pigment cells, and bones (Vinther, et al 2016).

So, yes: dinosaurs probably did really look like that.

It's personally gratifying to be able to say that. Philosophers don't often invite the question, but every semester I have at least one student ask if some reconstruction of a dinosaur is what the animal really looked like. They ask because my syllabi and introductory lectures often include strange and speculative dinosaur reconstructions. (Also: every surface in my office is covered with dinosaur toys.) My answer is one that philosophers do often give, if in response to different questions: "Maybe; it depends." For once, at least, I can give an answer more satisfying than that.

Still, I think there's value in the less definitive answer. It's the same value that I find in studying philosophy. The value is in this lesson: that we must become comfortable with uncertainty because there are truths that will be forever hidden from human eyes. I take the goal of paleontologists and philosophers alike to be finding novel ways to uncover such hidden truths. We construct arguments using the same cognitive tools with which we reconstruct dinosaurs, and so the latter strikes me as a great means of introducing students to the former.

"Dinosaur Philosophy"

I first started toying with dinosaur-focused introductory philosophy lectures after reading the paleoart manifesto All Yesterdays (Conway, et al 2013). That book was a catalyst for the "new look" movement in dinosaur reconstruction: Conway and his colleagues argued that paleoartists should depict dinosaurs as fatter, fluffier, and freakier than they've traditionally been restored.

Here's one (adorable) example of Conway's "unique and speculative" dinosaur art:

John Conway's reconstruction of the Australian dinosaur  Leaellynasaura.  From Conway,  et al  (2013).

John Conway's reconstruction of the Australian dinosaur Leaellynasaura. From Conway, et al (2013).

(I'll leave it to Adrian to post the image of a well-endowed Stegosaurus trying to have its way with a small sauropod.)

Did dinosaurs really look like that? Maybe; it depends.

The dinosaur depicted above--Leaellynasaura--is one for which we haven't yet found any evidence of feathers (or social behavior, for that matter). But--to quote every scientist I've ever known--absence of evidence isn't evidence of absence. We do know that Leaellynasaura lived in Australia during the lower Cretaceous period, when that continent was within the modern Antarctic Circle. It isn't unreasonable to think that a small animal living in an area with seasonal climatic variability might sport a coat of insulating feathers and forage in small groups. We don't have any evidence to prove this true, but that doesn't amount to a great argument for concluding the claim is false.

What Conway and his colleagues have highlighted is that, in the rare cases wherein we do find enough evidence to draw definite conclusions, a conservative approach to life reconstruction tends to get proved wrong. Consider Psittacosaurusreconstructions made before discovery of the Senkenberg specimen left out details that would have been obvious in the living animal. Who would have guessed at those tail bristles, for example? Consider other examples, too. Who would have guessed that hadrosaurs might show off rooster-like combs? Who would have guessed that a one-ton tyrannosauroid, large enough to thermoregulate through body size alone, also bore a coat of feathers? Conservative paleontologists who stuck to the bones wouldn't have guessed. Those paleontologists would have been wrong.

In most cases, bones are all we have. In those cases the true appearance of a dinosaur--including features like integument and coloration--is likely lost to us forever, hidden beneath the depths of geological time. Sure: paleoartists who speculate wildly about the appearance of dinosaurs might get their reconstructions wrong. But paleoartists who stay conservative are perhaps even more likely to be wrong.

Reconstructing the life appearance of dinosaurs therefore requires two things. The first is an ability to make well-reasoned judgments from available evidence. The second is comfort with the uncertainty that comes with drawing something that you can't see. Paleontologists and paleoartists can make educated guesses about animals that vanished 65 million years before the first of us appeared, but they can never see the animals themselves.

One of my courses is an introductory seminar titled "Dinosaur Philosophy," wherein I introduce students to basic philosophical concepts through examples from dinosaur paleontology. In that class I'll have students read Conway, et al (2013) and then ask them to create a grounded, but speculative, reconstruction of Tyrannosaurus rex. Students argue about details like whether or not T. rex's famous arms might have carried long display feathers, or if the animal was brightly or dully colored, or if it might have had some odd soft tissue structure for which we have no evidence whatsoever. (Neck frills are always popular. Thanks, Jurassic Park.) It's a fun debate, driven entirely by the shared belief that there is some hidden truth, obscured by the limits of our perceptions in space and time, that we can nevertheless stumble upon with the right mix of good luck and hard work.

And then we talk about eating babies.

Deep time and deep truths

Look: philosophy is a tough nut to crack. I openly acknowledge this. We ask our students to walk a tightrope of deference towards and criticism of the subject's authorities. These authorities disagree with one another. Their critics have critics. And here we are, two and a half millennia later, rehearsing the same disagreements and criticisms. I don't blame my students when they lament that the field seems to be a "circle." (I get that one more than I get the question about what dinosaurs look like.)

Each introductory philosophy instructor faces one supreme challenge on their first day of class: to bring students into that circle and keep them interested as they make their ways around. How do you convince the students that there's a point to it? How do you show them that there's a center to the circle?

I do it with dinosaurs.

Let me play the role of paleoartist. "Did Leaellynasaura have a yellow pom-pom on its tail?" you might ask. "Maybe; it depends," I'd answer. I might cite a reasonable disagreement between authorities. This disagreement might even last for a very long time. But your head wouldn't spin; you wouldn't conclude that both parties are right in their own ways. That conclusion would be very literally absurd.

But now let me play the role of philosophy instructor. "Is it always wrong to eat babies?" you might ask. "Maybe; it depends," I'd answer. Deontology says this and utilitarianism says that and now your head is spinning and it's no wonder that the first word that comes to mind is "circle." And without a clear resolution to the dispute, you might conclude (as students sometimes do) that philosophical disputes are grounded in personal taste more than anything else. (This certainly seems to be the case in ethics.)

Why reject the absurdity in the first case, but not in the second? Is it because the first question is an empirical one? That can't be it: time and geology have conspired to hide the empirical truth, leaving us to debate what we can infer from the few tantalizing clues that we can observe. Who's in the right about Leaellynasaura pom-poms? We can't say, but someone must be.

If I had to speculate (and I do because I'm not a psychologist), I would say that students reject the first absurdity and accept the second because they're more comfortable with uncertainty in the first case. We're a very long time separated from the last non-avian dinosaur, and so of course we shouldn't expect to know everything about them. But babies can get eaten here and now. If there's a true answer to the moral question then shouldn't we be able to find it?

Paleontologists refer to the geological span that separates us from the observation of dinosaurs as deep time. I use paleoart by analogy to introduce new philosophy students to the concept of what I call "deep truth." These are abstract truths hidden from us by the nature of our cognitive limitations, just as the appearance of dinosaurs is an empirical truth hidden from us by our spatio-temporal limitations. We can't observe deep truths, but we have some tantalizing clues hinting at what they might be. For example, traditional logic demands that if I say eating babies is always wrong and you say eating babies might sometimes be okay then we must be contradicting each other. That means that one of us is correct and one of us isn't. Who's in the right? We can't say, but someone must be.

A philosopher is someone who's learned to be comfortable with uncertainty about deep truths. We're uncertain because we recognize the quality of arguments given on both sides of the debates over the truths, as well as the fact that the arguments give us our only access to those truths. I'm pretty sure that I have a handle on the eating babies thing, but I'd be lying if I didn't admit that I harbor sincere concerns that I might be the one in the wrong. (But I am a vegetarian, so at least I'm erring far on the side of safety.)

John Conway's reconstruction of the  T. rex  specimen nicknamed "Stan," currently the author's favorite reconstruction of the species. From Conway,  et al  (2013).

John Conway's reconstruction of the T. rex specimen nicknamed "Stan," currently the author's favorite reconstruction of the species. From Conway, et al (2013).

I use paleontology to motivate my students' entry into philosophy because it was paleontology that prepared me to be a philosopher. Ever since I was two years old, I've wanted to know what T. rex really looked like. I've long since resigned myself to the fact that we'll probably never have a final resolution. With good luck and hard work we might come pretty close someday. If that's good enough for so important an issue as T. rex looks, then surely it's good enough for the deep truths of philosophy too.

That's what cracked the philosophical nut for me. By incorporating it into my teaching, hopefully it can do the same for new students.

Works Cited

  • Conway, J., Kosemen, C. M., Naish, D., & Hartman, S. (2013). All Yesterdays: Unique and Speculative Views of Dinosaurs and Other Prehistoric Animals. Irregular Books.
  • Vinther, J., Nicholls, R., Lautenschlager, S., Pittman, M., Kaye, T. G., Rayfield, E., Mayr, G., & Cuthill, I. C. (2016). 3D Camouflage in an Ornithischian Dinosaur. Current Biology.