In the end, the world makes fools of us all

There is a yet-unknown law of chaos theory which proposes an irreducible number of problems in the world: problems that cannot be solved, only moved around. This is not the astonishing conclusion of Princeton academic Edward Tenner, although it should be, since - after 100 examples of why human ingenuity is perpetually creating inadvertent new problems after the old ones have apparently been solved - he never actually tells us "why things bite back".

It seems the human race has a woeful record in predicting the results of its new drugs and machines, though we continue to act as if we always know what will happen. Perhaps every time a government minister gets up to bang on about "scientific evidence" we secretly know this: the BSE epidemic perfectly fits Tenner's "revenge effect" scenarios.

Why Things Bite Back concerns a philosophical problem bafflingly packaged as a scientific one, with all the familiar jolly eclecticism of popular science on view. The fact that Tenner has favoured the mild anthropomorphism of the tag "revenge effect" over the more accurate "recomplicating effect" gives pause for thought. Was not revenge once the favoured instrument of divine will?

These popular science books, with their origin stories, heresies, mysterious plagues and apocalyptic endgames, have the air about them of medieval religious disputations. How many angels can dance on a pinhead? How many revenge effects in the Exxon Valdez oil spill (where the sea-otters got herpes)? Medieval heretics would find much to please them in Tenner's book, at least the ones who considered all created matter was of the Devil. Of course, a pock-marked Cathar would say, things bite back because things come equipped with the teeth of demons.

Human ingenuity has taken some unexpected twists and turns. It's ironic that medicine - which caused a slew of iatrogenic diseases when it was "holistic" in the 18th-century and earlier - is slowly becoming holistic again, after realising that a century of successfully treating acute conditions has only revealed a raft of chronic ones underneath, which before nobody bothered about.

This innate confusion over what is a localised or a general effect is a striking theme, imperfectly examined by Tenner. Individuals gorging on antibodies have ruined their effectiveness for everyone else. Shore breaks on one beach create erosion elsewhere. Locally applied pesticides create super-pests and poison the consumer. Pollution from an individual's car trip to the shops is causing a child's fatal asthma attack.

It's a sorry tale, again and again, of human selfishness and Promethean scientific vanity (check out those 1950s "crocidolite" asbestos filters on cigarettes). We appear to be short-term animals with a long-term brain; creatures who evolved through an ability to solve problems effectively and quickly. Perhaps we need problems to feel alive, as an aspect of consciousness; perhaps we unconsciously engineer the revenge effect on ourselves.

In the end, Tenner's argument for "why things bite back" boils down to three propositions: first, we are all victims of our tendency to cut corners as a function of human ingenuity. Second, our predisposition to overreact when things go wrong and instigate the wrong solutions often blows up in our face. Finally the way we over-evolve our environment, way past our bodies' ability to deal with the consequences, poses a serious threat to human health.

It seems that scientists are now finding out what the rest of us have always known: that there's no such thing as a free lunch, a bottomless sea, an inert chemical or a patent medicine. Far from being a function of "chaos", this is all perfectly Newtonian. For every action there is a reaction. Perhaps science itself is a manifestation of the revenge effect; our irrational faith in its rationality may yet make fools of us all.