If the laws of nature had been chosen at random, with arbitrary values for the masses of the fundamental sub-atomic particles, the strengths of the forces, the thrust of the Big Bang and so on, the chances of life being able to develop anywhere within the universe would have been virtually zero. The life-friendly nature of the universe goes under the name The Anthropic Principle.
So, why is it thus? Was it deliberately designed that way? Or are there many universes, all running on different lines, with ourselves living in a freak universe that happens, purely by chance, to have all the right set of conditions? The latter possibility is known as the multiverse. But how could we ever hope to verify the multiverse hypothesis if we can only make contact with whatever is in our own universe?
Given that there must be many locations in the cosmos where life could have developed, we ask whether there are extraterrestrial forms of intelligent life. If so, how advanced are they likely to be? And what are our chances of ever finding out about them?