(Picture from here.)
The eastern gray tree frog (Hyla versicolor) and the Cope’s gray tree frog (H. chrysoscelis) are closely related. They look identical. Yet they only mate preferentially with each other. Why? You might ask. The Cope's frog has a higher pitched and faster paced call. Each species prefers its own species' call.
Cope's frog also has only half the chromosomes of the gray tree frog.
Sometime in the past, a Cope's frog spontaneously doubled its chromosomes and its offspring had a different call. In this case, it was matched by the female's preference for the same call.
Reproductive isolation is what defines a species and these frogs were isolated by a behavior rather than a physical trait. They were defined by an invisible uniqueness that they perceived easily but was difficult to penetrate without thorough examination. (See here, here and here.) Though they look alike, both species of frogs are unique.
The forefoot of the horse is actually its middle finger. The hoof is made of keratin—the same material of your fingernail. So, in one way the horse shares its foreleg structure with us. In another, it is unique. Other animals have hooves but the hooves aren’t quite the same. Other animals run but not quite the same as the horse. The horse, as I said, has commonality and uniqueness simultaneously.
Humans are a unique species.
Oh, I don’t mean that we have a Single Qualifying Trait that Signifies Our Specialness—there is no such trait. We have history and heritage from our relatives back to the fishes that, in part, share all our qualities. But that doesn’t detract from our uniqueness.
So we are with our brains. All vertebrates have vertebrate brains. All mammals have mammalian brains. All primates have primate brains. All humans have human brains. We can’t say humans don’t have mammalian brains in contrast to having human brains. That’s not a fact. That's not even an alternative fact. What we can say is that the set of characteristics that we use to define mammalian brains (and, for that matter, the set of characteristics we use to define mammals) encompasses the set of characteristics we use to define human brains.
There are additional brain characteristics shared among humans that are not shared with a chimp brain in the same way there are characteristics of the human shoulder that are not shared with the chimp shoulder.
I think it’s important to keep these sorts of things straight because we humans tend to expect biology to reinforce our cultural image of ourselves rather than tell us the truth. And, these days, truth is in short supply.
I’ve been reading Frans de Waal’s book, The Age of Empathy. I’ve been a de Waal fan ever since I read Chimpanzee Politics. (Which, by the way, I highly recommend. It follows the rise to power a particular chimpanzee male to alpha, his loss of power and how he regains it. After reading this book you’ll never watch House of Cards the same way again.)
Reading the Empathy is a little sad because it was published right in the aftermath of Obama’s first election and there’s a little glow of optimism all through it. Which is hard to take right now.
But the issues are still relevant. He points out that the individualistic, Ayn Rand-making-it-in-spite-of-all-odds-solely-on-our-own myth has very little basis in biology. Sure: individuals succeed. That’s how evolution works. That’s how human culture—not the same thing at all, by the way—works. But, for human beings, individuals succeed because of our cooperation not despite it.
Think of Andrew Carnegie. He starts off poor when he arrives in the USA. He works hard in the textile mill, learns telegraphy, gets promoted and does well. Educates himself and then invests in various things with profit and becoming, ultimately, one of the wealthiest men in the world. Was this due to his own efforts? Sure. Was it due solely to his own efforts? Maybe not.
Carnegie worked in a textile mill. Such a mill operates on the idea that many people must work together to produce product. They are paid in a fungible material called money—which operates because people agree on the rules by which it works. He educates himself using a library—a cooperative enterprise where the common material (books) is shared among a group of obligated individuals for the common good. He makes much of his fortune selling bonds—a group enterprise where a collection of people donates money to an endeavor that must be cooperatively achieved in order to profit on the result.
Carnegie could not have attained the wealth he achieved without his own drive and ambition. But he also could not have achieved it without a society of super-cooperative monkeys that agreed on the rules by which the society operated.
Here’s a quote from de Waal on the wiki page:
“Being both more systematically brutal than chimps and more empathic than bonobos, we are by far the most bipolar ape. Our societies are never completely peaceful, never completely competitive, never ruled by sheer selfishness, and never perfectly moral.”
America is an interesting place. It is a continuing tension between individual opportunity and the common good. A tension between doing what is morally right and what personally profitable. Much of our literature deals with this dichotomy. Every human society is a blend in balance but most places rely on homogenizing factors: race, religion, tribal heritage. America is based fundamentally on leaving the past and heritage behind and embracing who we are without past and heritage. It is also, fundamentally, based on preserving and nurturing the ideas and heritage we feel is absolutely essential.
The Puritans didn’t come over here to be rugged individuals. They came over for their own religious ideals. Even so, out of that came the Mayflower Compact and Roger Williams’ Providence Plantations. John Adams wrote a beautiful tract, Thoughts on Government, where he described good government as the mechanism for achieving happiness and virtue for the greatest number of people. As president, he also signed into law the Alien and Sedition Acts, which made it harder for immigrants to become citizens.
Jon Stewart said it best here: “This fight has never been easy…America is not natural. Natural is tribal. We’re fighting against thousands of years of human of human behavior and history to create something new.”
I think the fact that we—and by “we” I mean any group of human beings, American or not—can attempt to create something this unnatural is what makes us human.