Mental Bungee-jumping may not be your sport of choice, but there's a cerebral ledge that sooner or later each of us has to leap off. One day, ready or not, we glance in a mirror, cuddle an infant, attend a funeral, walk in the woods, partake of a substance Nancy Reagan warned us to eschew, chance a liaison, wake in the night with a napalm lobster in our chest, read a message from the pope or the Dalai Lama, get lost in Verdi or lost in the stars - and wind up thinking about our soul.

In general, America's cultural and political perspectives on the world outside of itself (spurred on by decades of its political and cultural isolationism on the part of the mass public) has produced a situation where good and evil are the defining, moral and cultural categories that are applied to make sense of a multitude of political situations both here and abroad. The simplicity of these categories forces us into a specific way of seeing the world, one which is metaphysical rather than political and with connotations of the supernatural rather than the sociological. Of course, it is arguable that such folk ways of seeing the world have been common to a mass public and that it has been the task of journalists and of intellectuals to melt away such fuzzy thinking through explanation and critical analysis. But the weeks following the tragic bombings at the World Trade Center and the Pentagon have shown that dividing the political and cultural universe into good and evil may be more pervasive and dangerous than previously expected.

Pure thought is not tainted by the thoughts of others or by petty "information," which the conservatives deem "knowledge." Intelligence is not the spouting of other people's facts and ideas. Thinking is not agreeing or disagreeing.

It means nothing to me that you memorize the rules of algebra and calculus. Make up your own mathematics while sitting, stoned in your bedroom. That is pure genius.

It is at least possible, then, and even seems likely, that machines will have the tool of deep and precise self-modification long before they have the understanding to use it effectively to achieve the ends they desire. For example, a machine capable of reading and revising its own code could probably figure out in a reasonable time how to enlarge its memory or lengthen its attention span. But what if it wanted to learn foreign languages more quickly or make funnier jokes? It's difficult to imagine that it could discover helpful code revisions, let alone necessary ones, without abundant trial and error. But trial and error in revising one's own code are about as hazardous as trial and error in brain surgery. If machines don't have precise knowledge to accompany their precise tools, or if they simply have incentives to experiment, then their experiments in self- modification will be fraught with the risks of self-mutilation and death.

Our climate is set to change irrevocably and unavoidably. It is not possible for all the human population of our present Earth to live as expensively as the Western elite. The Earth is just too vulnerable to be a remotely secure accommodation for humankind and its associates. Whether we retreat inside arcologies, or migrate into the Asteroid Belt, we are condemned to find a technological solution to the catastrophe - unless we are prepared to contemplate the death of our children and grandchildren in the droughts, floods, plagues and famines of the late 21^st century (I am being optimistic). We have to find out how things work, and how to build appropriate replicas of a working world, even while the way things work is changing. Where shall we put the peoples driven from coastal and island regions? What shall we do with peoples whose land has been eroded or leached clean of nutrients? What shall we do when antibiotics no longer work, animal diseases and plant blights sweep through our monocultures, and the working human population is too sick or too disillusioned to supply the needs of non-productive peoples? No doubt there is, for some, a certain pleasure in imagining the débacle. Some may even imagine that they can stockpile resources and ammunition enough to last out the time. The rest of us may prefer another future. For at the very same time that we can, with reason, expect these horrors, the same technological inventiveness and cultural versatility - and perhaps the same delusions of grandeur - that have been partly responsible for their likely onset, may promise us solutions.

You can tell that something unusual is going on these days by the way we draw our graphs. In normal times, we would use a linear scale to plot progress. The height of our graph would be proportional to the measure of progress. But we live at a remarkable moment in history, when progress is so rapid that we plot it on a logarithmic scale.