Peter asked:

It is widely accepted that there is a high probability of intelligent life on other planets. Given that there is so much we don’t know about how life began, that seems a sensible judgement.

But suppose we discovered evidence that made it extremely likely that the human race is alone. Intelligent life has just one shot to get things right, and if we screw up then there are no more chances, ever.

Would that make a difference to how we live? (I’m thinking of global warming, nuclear proliferation, etc.)

Answer by Jürgen Lawrenz

I do question the supposition ‘that there is a high probability of intelligent life on other planets’. It is a conjecture based entirely on the rise of intelligent life on earth, and there is not a smidgin of actual evidence from anywhere else, not even the solar system. In short, we simply extrapolate from the evolution of life on earth a handful of principles which could conceivably occur elsewhere in the universe. But it is not a compelling argument.

So the evidence you ask for, that the human race may be alone, is more powerful than the contrary supposition. And so to your question: What if we succeed in screwing it up?

I would suggest to you that it would mean the end of only a particular form of intelligence. We have a tendency of exalting it, even to the extent of dreaming about ‘theories of everything’ and playing God with genetically modified life forms. But clearly, if it were to end in a nuclear catastrophe, any putative aliens watching could come to only one conclusion: That our supposed intelligence was far outweighed by our collateral stupidity.

What then? The earth would be rid of a dangerously delusional and immensely rapacious life form. And since all evolutionary evidence points to failed gene pools never being re-used, we would not get a second chance. But intelligence itself would endure, because nuclear fallout does not affect the survival of anaerobic life forms. Let’s not forget that on a 36-hour clock, Homo sapiens is only 2-3 seconds old; that’s all it has taken for the human brand of intelligence to misfire. But the possibilities and opportunities for other kinds of intelligence to emerge from our fiasco are endless in the geological long-term view.

Keeping a terminal scenario before our eyes should obviously affect the way we live. But we humans are also an extremely short-sighted species. We can hardly plan for more than one generation into the future. Thus we think nothing today of the possibility that we are robbing our grand-children of maybe half or all the resources of civilisation that we still enjoy. That’s not very intelligent and the negative imprint of our vaunted intelligence. Paraphrasing Schopenhauer, we humans have accustomed ourselves to employing our intellect to furnish us with cogent arguments in support of the stupid things we do. It’s a very pessimistic view on our future; but unless the many find ways of depriving the few of the power with which they bring ruin on our head, we can only hope that there is really a God who won’t let it happen!