On first hearing, it seems a bit of a wide ball. But I find this thought experiment of the cosmologist George Ellis fascinating.

Imagine one day we make contact with sentient, intelligent beings on another planet. Imagine too that we can communicate.

One area in which we might expect to be able to communicate would be in relation to mathematics. We’d expect smart aliens to have concepts comparable to our own, since mathematics is universal: 1+1=2 whether you're on earth or Gliese 581c.

Would the same be true for ethics? After all, a moral sense seems to be a universal human phenomenon, for good or ill. Moreover, although different ethical systems have evolved more or less independently on planet earth, they do show remarkable similarities. All the leading axial figures ??" Jesus, Socrates, the Hebrew prophets, the Buddha, Laozi ??" taught what is sometimes called kenotic ethics - from the Greek for 'emptying' - the notion that the good is discovered by losing yourself.

Jesus taught losing life to gain it. To talk with Socrates was to question everything about what you thought you knew about yourself. The prophets felt possessed by God not themselves. Buddha discovered the emptiness of the self. Laozi taught something pretty similar in the search for the nameless, the tao.

Alternatively, there is what has come to be called the Golden Rule: to do to others as you would have done to yourself. It's another decentering way of life. Kant derived the principle by reason at the time of the Enlightenment. Today, evolutionary psychologists seem to be feeling their way towards an idea that is almost the same again (though they tend to interpret it as a strategy for survival and resist its moral implications.)

Thus, we might expect sentient intelligent beings on another planet to have kenotic, moral ideals comparable to our own - alongside similar struggles with trying to live up to them, of course.

And if we did? Well, it would suggest that, like the Platonic conception of mathematics, morality is somehow written through the fabric of the universe. Or if you prefer an emergent account of things, that it is not just consciousness that emerges out of the cosmos, or even self-consciousness, but maybe moral consciousness.

I suppose you could claim the status of scientific theory for the thought experiment. After all, it is in principle falsifiable: the discovery of a planet inhabited by psychotic extraterrestrials, with no moral sense, would destroy the thought experiment. That said, we might not want to make contact with such creatures, for they could presumably decide to destroy us too.

Or, staying with that last thought: given that ET exists, maybe the fact that we haven't been destroyed by ET is evidence that ET is moral.

Conversely, if you feel the universe is basically an amoral place and humans are an ethical exception, that we haven't been destroyed might be evidence that there simply isn't advanced intelligent life on other planets.