Nineteenth-century naturalists used their warm blood/cold blood dichotomy to classify all vertebrates into two grand divisions, one above the other. (lifelike dinosaur costume)At the bottom were the “lower vertebrates,” the classes without metabolic control of their body heat. Here were lumped all the fishes, the Amphibia, and of course the Reptilia. At the top were the “higher vertebrates,” the two classes— Aves and Mammalia.(Real dinosaur costume) Dinosaurs were thrown into the Reptilia and so into the “lower vertebrates” by early naturalists, but an equally good case could have been made to classify dinosaurs as primitive birds. No one, either in the nineteenth century or the twentieth, has ever built a persuasive case proving that dinosaurs as a whole were more like reptilian crocodiles than warm-blooded birds. No one has done this because it can’t be done.
Generally speaking badges are harmful in science.(Realistic Animatronic dinosaur) If a scientist pins one labeled “Reptile” on some extinct species, anyone who sees it will automatically think, “Reptile, hmmm . . . that means cold-blooded, a lower vertebrate, sluggish when the weather is dark and cool.” There are never enough naturalists around, in any age; so most scientific orthodoxy goes unchallenged. There are just not enough skeptical minds to stare at each badge and ask the embarrassing question, “How do you know the label is right?”
Be kind to colleagues, ruthless with theories, is a good rule. (mechanical dinosaur model)A scientific theory isn’t merely idle speculation, it’s a verbal picture of how things might work, how a system in nature might organize things—atoms and molecules, species and ecosystems. But old paleontological theories too often aren’t treated roughly enough. Old theories—like the reptilian nature of dinosaurs—are accepted like old friends of the family. You don’t yell at old Aunt Cecilia. So hundred-year-old dinosaur theories live on without being questioned, and too often they are assumed to be totally correct. Even when such theory is caught in an error, it’s likely to be excused.