“When ideas have sex” is science writer Matt Ridley’s provocative way of describing innovation in his new book, “The Rational Optimist.”

Ridley’s hypothesis is that it is trade, in both goods and ideas, that makes Homo Sapiens so successful:

“(A)fter millions of years of indulging in reciprocal back-scratching of gradually increasing intensity, one species, and one alone, stumbled upon an entirely different trick. Adam gave Oz an object in exchange for a different object… the extraordinary promise of this event was that Adam potentially now had access to objects he did not know how to make or find; and so did Oz. People traded goods, services and, most important, knowledge, creating a collective intelligence: Ten individuals could know between them ten things, while each understanding one.”

Rulers are fond of taking credit for advances during their tenure and scientists see their work as the reason for technological advancement progress. Dr. Ridley says, au contraire! It is trade that creates the prosperity and leisure time for science to flourish and it is entrepreneurial tinkerers who are more likely to create the inventions that liberate us from washing our clothes in creeks and churning our butter by hand.

“The modern world is a history of ideas meeting, mixing, mating and mutating… the reason that economic growth has accelerated so in the past two centuries is down to the fact that ideas have been mixing more than ever before.”

If bottom-up innovators are allowed to prevail, free of rigid rules or parasitic interference, Ridley predicts “Prosperity spreads, technology progresses, poverty declines, disease retreats, fecundity falls, happiness increases, violence atrophies, freedom grows, knowledge flourishes, the environment improves and wilderness expands.”

Ridley declares our progress is unsustainable if we stifle innovation and trade, the way China and other empires have in the past. Banning technologies by requiring advance proof that they’re 100 percent without risk or sabotaging the free flow of trade and people via byzantine visa restrictions or paranoid security requirements are all ways we can sabotage humanity.

We often don’t truly understand the complex ways in which civilization and human society are created, advance, or retreat. “When ideas have sex” as presented in “The Rational Optimist” is an intriguing, entertaining tour de force on human history from a fascinating perspective.

(Drawn from a New York Times article, “Doomsayers Beware, a Bright Future,” by John Tierney, published May 18, 2010 in the New York City edition.)