Homo Mysterious: Evolutionary Puzzles of Human Nature (50 page)

Yet another unresolved mystery concerns our own evolutionary future. Here, at last, we confront an enigma that is not only unanswered but also genuinely unanswerable. That is, we cannot predict with any reliability the precise course of our future evolution—where our species will end up, at any given time in the future—although we can have substantial confidence as to the force (natural selection) that will be powering our journey. Not long ago, it was widely thought that future human beings will have small bodies (because with the advent of technology, people aren’t as physically active as they used to be) and large heads (because, presumably, they will be thinking more). In H. G. Wells’s
Time Machine
, humanity in the distant future consists of the rapacious, bestial Morlocks (troglodytic descendants of industrial workers) and naïve, childlike Eloi, upon whom the Morlocks feed. More recently, the movie
Wall-E
portrayed bloated humanity, as a result of the obesity epidemic and excessive reliance upon machines.

None of these images is likely to be even close to accurate, because each is based, unknowingly, on assumed Lamarckian inheritance: the old, discredited notion that, for example, giraffes evolved long necks because their ancestors stretched those necks to reach food, after which their extended anatomy was somehow passed on to their descendants. Or that body builders, as a result of developing large muscles in their lifetime, would pass such traits to their offspring.

But in fact, the only way future human beings would have large heads or obese bodies is if people with large heads or obese bodies (based on their genetic makeup, not their dietary or exercise habits) had proportionately more than their share of children. Unlikely.
And in view of enhanced communication and transportation, it is overwhelmingly probable that gene exchange among different ethnic and socioeconomic groups will keep us one species (goodbye to any dichotomous future, á la Morlocks and Eloi).

On the other hand, evolution by natural selection definitely has not ceased in our own species, any more than in others. Evolution is, in fact, unavoidable whenever some people are more effective than others in projecting their genes into the future; what changes are the “selection pressures,” the factors that convey benefit or liability to particular traits, not the reality of differential reproduction and with it, the inevitability of natural selection and evolutionary change. In the distant past, for example, selection favored bipedalism, large brains, consciousness, etc., for reasons we have just speculated about. What will it favor in the future? Maybe the ability to reproduce despite strontium-90 in our bones and PCBs in our fat. Or perhaps a susceptibility to fundamentalist religious teaching. If resource scarcity becomes increasingly severe, maybe natural selection will smile upon smaller, more efficient human beings, who can thrive and reproduce using fewer calories and requiring less space, or who are not especially stressed by an increasingly polluted, globally overheated world with greatly diminished biodiversity. With increasing in vitro fertilization—not to mention cloning—it is conceivable (and perhaps, desirable) that males may eventually vanish altogether, or at least, that the various traits that have evolved in the service of human “mate selection” will disappear, to be replaced by … who knows what.

Stay tuned. (Note to my editor at Oxford University Press: Maybe we should start thinking about a follow-up book,
Homo Mysterious
v.2.0, to cover the “missing link,” crying, laughing, yawning, blushing, suicide, morality and ethics, the unconscious, the evolution of emotions, and our evolutionary future, as well as some of the other mysteries that must, for now, remain especially mysterious.)

“Just as people find water wherever they dig, they everywhere find the incomprehensible, sooner or later.” So wrote Georg Christoph Lichtenberg, 18th-century physicist and satirist. More than two centuries later, it isn’t at all clear that people will find water
wherever
they dig. Nor is it certain that wherever we dig in the realm of life, we shall find the incomprehensible. The point of
this book, in fact, has been just the opposite: that we ourselves
are
comprehensible, even though we aren’t at present altogether comprehended.

The alternative to mystery isn’t triviality or boredom. Rainbows are no less beautiful when we understand that they are produced by sunlight separated into its spectral components, just as life is not rendered tedious when seen as structured by nucleic acids rather than as
élan vitale
. Or when evolution is seen as the ultimate force behind that structuring. Or when human beings are seen as inextricably connected to the whole business. Rather, as Darwin famously wrote at the conclusion of
The Origin of Species
, “There is grandeur in this view of life.”

There is a chilling moment toward the end of Ray Bradbury’s science fiction classic,
The Martian Chronicles
, when a human family, having escaped to Mars to avoid impending nuclear war, looks eagerly into the “canals” of their new planetary home, expecting to see Martians. They do: their own reflections. It wasn’t terribly long ago that reputable astronomers entertained the notion that there really were canals on Mars. From our current vantage, this is clearly fantasy, and yet, Mars has not become any less intriguing for its becoming known, just as the moon didn’t lose any appreciable panache once it became undeniably made of rock rather than green cheese.

The same applies to ourselves. Unlike Bradbury’s fictional family, we really
can
see ourselves, if we simply look hard enough. Just as the philosopher Immanuel Kant once proposed
Sapere Aude
(“Dare to Know”) as a motto for the Enlightenment,
Homo Mysterious
has proposed a modification: “Dare to Know How Much We Don’t Know.” And in the process, perhaps you have been inspired to dare even more: to help diminish the existing quantity of Unknown, or at least to cheer those who are struggling to do so, all the while knowing that more unknowns will arise, and that complete “success” is therefore impossible.

This can lead, unfortunately, to a more cynical perspective, which for obvious reasons I have elected to mention only here, at the end of our current intellectual journey. Put forth by the Polish philosopher Leszek Kolakowski, it has been called the Law of the Infinite Cornucopia: For any belief, it is always possible to come up with a seemingly unlimited amount of supporting evidence.
By the same token, perhaps it will always be possible to come up with plausible but ultimately unsatisfying explanations.

Unlike Sisyphus, however, who was condemned to spend eternity pushing a huge rock up a steep hill only to have it roll back down again, the scientific push for greater knowledge doesn’t slip backward (at least, not for long)—although it never reaches a safe, secure, tedious, and satisfactory stopping point. There are always more hills to climb.

It might also help to recall a different parable, in which two brothers are told to dig for treasure in the family vineyard. They found neither gold nor silver, but their labors greatly enriched the soil.

Aarssen, Lonnie W., 301

acorn woodpeckers, behavior, 123

acorn worm, behavior, 124

adaptive overshoot hypothesis, science and religion, 222–224, 225, 227

adaptive parsimony, principle, 142

adaptive vs. good, religion, 218–221

addiction hypothesis, 231

African Americans, escaping slavery, 215

AIDS, 92, 134, 205

albatrosses, female-female pairing, 131

Alexander, Richard D., 283

Alice in Wonderland
, Carroll, 176
n

alleles

alternative forms of same gene, 90

homosexuality-promoting, 116

sex-orientation, 100

sickle cell anemia, 112–113

allo-mothering, child-rearing, 108

allo-parenting, cooperative breeding, 71

altruism

evolution of, 253

genes, 197

group selection, 254

homosexuality, 104

reciprocal, 285

amenorrhea, signal, 13

Americans with Disabilities Act, 164

Androgynes, kinds of, 94

And Tango Makes Three
, children’s book, 99

animals

mountings, 96, 97, 123–124, 132–133

same-sex behavior, 127–128

same-sex pairing, 97

social cooperation, 255

appearance and dress, female vs. male, 75–76, 77

Archilochus, 162

Aristophanes, 94

Aristotle,
Poetics
, 169

Armstrong, Karen,
A History of God
, 196

Art and Intimacy: How the Arts Began
, Dissanayake, 159

The Art Instinct
, Dutton, 155, 164

arts

biological roots, 147–149

cave, 148

chameleon effect, 162

cheesecake hypothesis, 149–153

children, 157–158

cross-cultural human universal, 145–146, 158

evolutionary origin, 145, 162–165

from cracked kettles to spandrels, 153–157

gossip and theory of mind, 174–176

learning and play, 167–174

manifestations, 146

pleasure from, 174

pleasures, penchants and misunderstandings, 187–191

portrait of artist as show–off, 176–187

search, 144–149

social payoff, 157–162

spandrel hypothesis, 154–156

asexual reproduction, 83, 84

Athens, 162–163

attractiveness, fitness, 27

Auden, W. H., 149

Autobiography
, Darwin, 223

autosomal chromosomes, 67, 100

Azande, Africa, 216

Azande, religion, 216

Aztecs, military success, 242–243

Bach, J. S., 171

Bacon, Francis, 196

Bagemihl, Bruce, 98

balanced polymorphisms, genetics, 112–113

banker’s paradox, 39

Barash, David,
Madame Bovary’s Ovaries
, 171

Baudelaire, 189

Becker, Ernest, 298, 301

Beethoven, 158, 189

Benthall, Jonathan, 199

Bergson, Henri, 169

Berlin, Isaiah, 162, 190, 191

Bierce, Ambrose, 268, 269
n

Biological Exuberance: Animal Homosexuality and Natural Diversity
, Bagemihl, 98

biology

art, 147–149, 173

communicative signals, 308–309

evolutionary, 7, 8

God gene, 195–196

Krebs cycle, 196

music, 147, 149

poetry, 149

religious behavior, 203–206

science, 5

biparental behavior, partnerships, 24–25

bipedalism, 267, 280

birds

acorn woodpeckers, 123

copulations, 31

delayed plumage maturation, 128

“helpers at the nest” phenomenon, 106, 107
n

same-sex pairings, 130–131

birth control, rhythm method, 22

birth order, homosexual play, 129

Blake, William, 229

blood of Christ, Eucharist, 4

Bohr, Niels, 7, 217
n

bonding, concealed ovulation, 25–27

Book of Job, human ignorance, 234

boredom hypothesis, arts, 156

The Botany of Desire
, Pollan, 207

bottlenose dolphins, male-male cooperation, 121–122

Boyd, Brian, 148, 163, 168, 169, 170, 171, 172, 187, 188

Boyer, Pascal, 213

Bradbury, Ray, 312