Nineteenth-century English poet John Keats once bemoaned that Isaac Newton had “Destroyed the poetry of the rainbow by reducing it to a prism.” Natural philosophy, he lamented, “Will clip an Angel’s wings/Conquer all mysteries by rule and line/Empty the haunted air, and gnomed mine/Unweave a rainbow.”

Does a scientific explanation for any given phenomenon diminish its beauty or its ability to inspire poetry and emotional experiences? I think not. Science and aesthetics are complementary, not conflicting; additive, not detractive. I am nearly moved to tears, for example, when I observe through my small telescope the fuzzy little patch of light that is the Andromeda galaxy. It is not just because it is lovely, but because I also understand that the photons of light landing on my retina left Andromeda 2.9 million years ago, when our ancestors were tiny-brained hominids. I am doubly stirred because it was not until 1923 that astronomer Edwin Hubble, using the 100-inch telescope on Mount Wilson in the hills just above my home in Los Angeles, deduced that this “nebula” was actually a distant extragalactic stellar system of immense size. He subsequently discovered that the light from most galaxies is shifted toward the red end of the electromagnetic spectrum (literally unweaving a rainbow of colors), meaning that the universe is expanding away from its explosive beginning. That is some aesthetic science.

No less awe-inspiring are recent attempts to unweave the emotions, described by anthropologist Helen Fisher of Rutgers University in her book Why We Love (Henry Holt, 2004). Lust is enhanced by dopamine, a neurohormone produced by the hypothalamus that in turn triggers the release of testosterone, the hormone that drives sexual desire. But love is the emotion of attachment reinforced by oxytocin, a hormone synthesized in the hypothalamus and secreted into the blood by the pituitary. In women, oxytocin stimulates birth contractions, lactation and maternal bonding with a nursing infant. In both women and men it increases during sex and surges at orgasm, playing a role in pair bonding, an evolutionary adaptation for long-term care of helpless infants.

At the Center for Neuroeconomics Studies at Claremont Graduate University, Paul J. Zak posits a relation between oxytocin, trust and economic well-being. “Oxytocin is a feel-good hormone, and we find that it guides subjects’ decisions even when they are unable to articulate why they are acting in a trusting or trustworthy matter,” Zak explained to me. He argues that trust is among the most powerful factors affecting economic growth and that it is vital for national prosperity for a country to maximize positive social interactions among its members by ensuring a reliable infrastructure, a stable economy, and the freedom to speak, associate and trade.

We establish trust among strangers through verification in social interactions. James K. Rilling and his colleagues at Emory University, for instance, employed a functional magnetic resonance imaging (fMRI) brain scan on 36 subjects while they played Prisoner’s Dilemma. In the game, cooperation and defection result in differing payoffs depending on what the other participants do. The researchers found that in cooperators the brain areas that lit up were the same regions activated in response to such stimuli as desserts, money, cocaine and beautiful faces. Specifically, the neurons most responsive were those rich in dopamine (the lust liquor that is also related to addictive behaviors), located in the anteroventral striatum in the middle of the brain — the so-called pleasure center. Tellingly, cooperative subjects reported increased feelings of trust toward, and camaraderie with, like-minded partners.

In Charles Darwin’s “M Notebook,” in which he began outlining his theory of evolution, he penned this musing: “He who understands baboon would do more towards metaphysics than Locke.” Science now reveals that love is addictive, trust is gratifying and cooperation feels good. Evolution produced this reward system because it increased the survival of members of our social primate species. He who understands Darwin would do more toward political philosophy than Jefferson.

The most common explanation for the Bounty mutiny pits a humane Fletcher Christian against an oppressive William Bligh. In her 2003 revisionist book, The Bounty, Caroline Alexander recasts Bligh as hero and Christian as coward. After 400 pages of gripping narrative, Alexander hints that the mutiny might have involved “the seductions of Tahiti” and “Bligh’s harsh tongue” but concludes that it was “a night of drinking and a proud man’s pride, a low moment on one gray dawn, a momentary and fatal slip in a gentleman’s code of discipline.”

A skeptic’s explanation may seem less romantic, but it is more intellectually satisfying because it is extrapolated from scientific evidence and reasoning. There are, in fact, two levels of causality to consider: proximate (immediate historical events) and ultimate (deeper evolutionary motives). Both played a role in the Bounty debacle.

A count of every lash British sailors received from 1765 through 1793 while serving on 15 naval vessels in the Pacific shows that Bligh was not overly abusive compared with contemporaries who did not suffer mutiny. Greg Dening’s Mr. Bligh’s Bad Language computed the average percentage of sailors flogged from information in ships’ logs at 21.5. Bligh’s was 19 percent, lower than James Cook’s 20, 26 and 37 percent, respectively, on his three voyages, and less than half that of George Vancouver’s 45 percent. Vancouver averaged 21 lashes per man, compared with the overall mean of five and Bligh’s 1.5.

If unusually harsh punishment didn’t cause the mutiny, what did? Although Bligh preceded Charles Darwin by nearly a century, the ship commander comes closest to capturing the ultimate cause: “I can only conjecture that they have Idealy assured themselves of a more happy life among the Otaheitians than they could possibly have in England, which joined to some Female connections has most likely been the leading cause of the whole business.”

Indeed, crews consisted of young men in the prime of sexual life, shaped by evolution to bond in serial monogamy with women of reproductive age. Of the crews who sailed into the Pacific from 1765 through 1793, 82.1 percent were between the ages of 12 and 30, and another 14.3 percent were between 30 and 40. When the men arrived in the South Pacific, the results, from an evolutionary point of view, were not surprising. Of the1,556 sailors, 437 (28 percent) got the “venereals.” The Bounty’s infection rate was among the highest, at 39 percent.

After 10 months at sea, Bligh was not surprised by the reaction to the natives: “The Women are handsome … and have sufficient delicacy to make them admired and beloved — The chiefs have taken such a liking to our People that they have rather encouraged their stay among them than otherwise, and even made promises of large possessions. Under these and many other attendant circumstances equally desirable it is therefore now not to be Wondered at … a Set of Sailors led by Officers and void of connections … should be governed by such powerfull inducement … to fix themselves in the most of plenty in the finest Island in the World where they need not labour, and where the alurements of disipation are more than equal to anything that can be conceived.”

Neuroscience shows that the attachment bonds between men and women, especially in the early stages of a relationship, are chemical in nature and stimulate the pleasure centers of the brain in a manner resembling addictive drugs. In her book The Oxytocin Factor, for example, Kerstin Uvnäs-Moberg shows that oxytocin is secreted into the blood by the pituitary gland during sex, particularly orgasm, and plays a role in pair bonding, an evolutionary adaptation for long-term care of infants.

Ten months at sea weakened home attachments of the Bounty’s crew. New and powerful bonds made through sexual liaisons in Tahiti (that in some cases led to cohabitation and pregnancy) culminated in mutiny 22 days after departure, as the men grew restless to renew those fresh attachments; Christian, in fact, had been plotting for days to escape the Bounty on a raft.

Proximate causes of mutiny may have been alcohol and anger but the ultimate reason was evolutionarily adaptive emotions expressed nonadaptively, with irreversible consequences.