Today, let's think about liability. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

For six hundred years the Babylonians evolved a body of law. These laws were carved on a stone during the rule of Hammurabi in the 18th century BC, and that stone was rediscovered in 1901.

This so-called "Code of Hammurabi" says little about punishing murder, but woe betide anyone guilty of negligence: The surgeon who bungles an operation loses a hand. The mason whose building collapses is punished on a sliding scale. If the owner is killed, the mason himself is executed. If the owner's son dies, then so must the mason's son, and so forth. The code isn't for the squeamish. It specifies punishment by amputation, impalement, drowning, immolation, and enslavement -- all with blood-chilling abandon.

Getting things right is a far bigger worry in today's dense technology than it was 4000 years ago. Yet we don't threaten to amputate surgeons' hands or kill engineers' children. And our resulting technologies are generally pretty safe. Only one person in ten million dies each year from structural failures of buildings. Americans flew ten million commercial flights in 1980 and '81 without a single fatality.

Our equation for preserving safety is different from Hammurabi's. A world that depends on technology has to allow some risk. Trying to function in perfect safety would make technology hopelessly static and without vitality. So we set the levels of acceptable risk and then punish the engineer who's reckless.

Of course, we aren't even-handed about it. We accept familiar kinds of accidents but impose extremely high standards on unfamiliar technologies. For example, we accept thousands of deaths each year from using coal to generate power -- deaths from mine cave-ins, emphysema, coal-trucking accidents, and so on. On the other hand, our safety record in the nuclear-power industry is almost perfect, and that's because death from a radioactive leak is alien. Since we find it far more terrifying than death in a trucking accident, we guard more carefully against it.

The result is that American nuclear-power construction has been brought to a halt -- by skyrocketing safety-related costs and by resulting delays. But coal-fired plants, with their associated death rates, go right on, and few people give them a thought.

We have to look clearly at risk. New inventions are alien, and we never quite know where one will take us. Threatening to chop off inventors' hands can only hurt badly-needed development. Yet we can't be casual about the terrible dangers each new technology poses. I don't have a Hammurabic formula for striking these balances; but in a complex world they have to be struck.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Hammurabi, The Hammurabi Code, And the Sinaitic Legislation, With a Complete Translation of the Great Babylonian Inscription Discovered at Susa, By Chilperic Edwards. Port Washington, NY: Kennicat Press, 1971.