Finding extra-terrestrial life would no doubt be one of the most exciting discoveries of our time and would revolutionise so much of what we know about ourselves and our universe. The debate on the likelihood of us ever encountering something resembling 'life' continues unabated. What will it look like? Will it be bacteria-like? Will it be intelligent (as we define it)? Will we be able to communicate with it? If a super-intelligent life-form exists out there, why has it not found us yet?
NASA has its own research institute to mull over such questions - SETI - The Search for ExtraTerrestrial Intelligence. We also have an entire field of study called 'Astrobiology' which, as the name suggests, takes biology beyond our planet. In one way or another the topic has been the subject of numerous books, films, TV shows, and conspiracies, with the aliens often turning out to be monstrous villains with a bizarre and inexplicable need to probe their human captives in all sorts of strange places.
Had there been something resembling a 'space race' in the 19th century, perhaps we might have had similar stories passed down to us from our ancestors. As it happened, neither biology nor astronomy had reached anywhere near the level of sophistication necessary for such a subject to be widely considered and discussed. But a rare and omnivorous (though not entirely infallible) intellect at this time who did look up at the starry skies to wonder about such a topic was the biologist T.H. Huxley:
"...the assumption that, amidst the myriads of worlds scattered through endless space, there can be no intelligence, as much greater than man's as his is greater than a blackbeetle's; no being endowed with powers of influencing the course of nature as much greater than his, as his is greater than a snail's seems to me not merely baseless, but impertinent."
This was in fact one of Huxley's key arguments for being an 'agnostic', a term which he was the first to coin. From his "rigidly scientific point of view", it appeared that:
"If our intelligence can, in some matters, surely reproduce the past of thousands of years ago and anticipate the future, thousands of years hence, it is clearly within the limits of possibility that some greater intellect, even of the same order, may be able to mirror the whole past and the whole future; if the universe is penetrated by a medium of such a nature that a magnetic needle on the earth answers to a commotion in the sun, an omnipresent agent is also conceivable; if our insignificant knowledge gives us some influence over events, practical omniscience may confer indefinably greater power."
Despite this view, he posited that simply believing that something 'might be' in no way confirms the existence that 'it is'. As such, the only rational stance in such cases was for a person to admit that "they know what they are quite aware they do not know".
In our search for extra-terrestrial life, it appears that this might also be the wisest approach to take. Perhaps something is out there, perhaps not—we are quite aware that we do not know—and so we continue in our role as cosmic detectives, all while humbly admitting to the limitations of our knowledge and marvelling at the mysteries of our universe, a vast and seemingly endless ocean in which we shall forever remain little more than an infinitesimal drop.