Humanity occupies a very small place in an unfathomably vast Universe. Travelling at the speed of light – 671 million miles per hour – it would take us 100,000 years to cross the Milky Way. But we still wouldn’t have gone very far. By recent estimates, the Milky Way is just one of 2 trillion galaxies in the observable Universe, and the region of space that they occupy spans at least 90 billion light-years.Well, it doesn't. At least it doesn't given both Hughes' and Sagan's atheism. Significance cannot be conferred on humanity by the cosmos any more than it can be conferred on us, to borrow Hughes' comparison, by a pile of rocks. It can only be conferred by a person who values us, but then we are only significant to that person (and to ourselves, too, I assume). For humanity as a whole to have significance it must have value to a person who stands outside humanity.
If you imagine Earth shrunk down to the size of a single grain of sand, and you imagine the size of that grain of sand relative to the entirety of the Sahara Desert, you are still nowhere near to comprehending how infinitesimally small a position we occupy in space. The American astronomer Carl Sagan put the point vividly in 1994 when discussing the famous ‘Pale Blue Dot’ photograph taken by Voyager 1. Our planet, he said, is nothing more than ‘a mote of dust suspended in a sunbeam’.
And that’s just the spatial dimension. The observable Universe has existed for around 13.8 billion years. If we shrink that span of time down to a single year, with the Big Bang occurring at midnight on 1 January, the first Homo sapiens made an appearance at 22:24 on 31 December. It’s now 23:59:59, as it has been for the past 438 years, and at the rate we’re going it’s entirely possible that we’ll be gone before midnight strikes again. The Universe, on the other hand, might well continue existing forever, for all we know. ...our time on this mote of dust will amount to nothing more than a blip. In the grand scheme of things we are very, very small.
For Sagan, the Pale Blue Dot underscores our responsibility to treat one another with kindness and compassion. But reflection on the vastness of the Universe and our physical and temporal smallness within it often takes on an altogether darker hue. If the Universe is so large, and we are so small and so fleeting, doesn’t it follow that we are utterly insignificant and inconsequential?
This thought can be a spur to nihilism. If we are so insignificant, if our existence is so trivial, how could anything we do or are – our successes and failures, our anxiety and sadness and joy, all our busy ambition and toil and endeavour, all that makes up the material of our lives – how could any of that possibly matter?
Hughes suggests that this is at least part of the appeal of theism. If there is no God then humanity has no more significance than a swarm of bacteria in a fetid pond. If, however, there is a God who created us and all else then how big we are and how big the cosmos is by comparison are simply irrelevant facts, as are the facts about how distressingly short our life span is. What matters is that we have value, and therefore significance, to the God who made us.
Hughes doesn't believe there is a God, though, so he's understandably reluctant to accept this solution to his problem:
The pessimistic view, then, is that, because we occupy such a small and brief place in the cosmos, we and the things we do are insignificant and inconsequential. But is that right? Are we insignificant and inconsequential? And if we are, should we respond with despair and nihilism?Nihilism and despair would seem to be a rational, though not very attractive, response, but Hughes spends the balance of his essay trying to avoid it. He mentions, but doesn't agree with, an analogy put forward by Guy Kahane, a philosopher at Oxford:
A single diamond sitting on display in a huge empty warehouse might be small by comparison with its surroundings, but that doesn’t mean that it’s insignificant or that it merits no attention. Since, Kahane argues, the primary source of value is intelligent life, it follows that our cosmic significance depends on how much intelligent life there is out there. If the Universe is teeming with it, if we are just one diamond among millions or billions of others, many of which are just as large and bright, or more so, then we are indeed cosmically insignificant. If, however, we are the sole exemplars of intelligent life, then we are of immense cosmic significance: we are a single diamond shining forth, surrounded by nothingness, like an incandescent beacon of light in the Stygian night.This seems wrong to me. The only reason a solitary diamond has any significance at all is because we assign it value. If a solitary diamond were surrounded by an endless void it would have no significance at all, and if we're surrounded by nothing but mindless, impersonal atoms then neither do we.
Hughes concludes his essay on a melancholy note. I think he intends it to be a brave affirmation of significance, but it sounds more like whistling past the graveyard. He concedes that we might be insignificant in the grand scheme of things, but we still have things that matter to us,
[T]he things that we care about most – our relationships, our projects and goals, our shared experiences, social justice, the pursuit of knowledge, the creation and appreciation of art, music and literature, and the future and fate of ours and other species – do not depend to any considerable extent on our having control over a vast but largely irrelevant Universe.Yes, these things matter to us, or at least some of us, but why should they? If we're all just doomed specks of dust what does our music and social justice matter? Is not our insistence on the significance of these things like the insistence of a condemned man that it's important that he make the bed in his jail cell before being led off to the gallows? The significance we give these things is little more than an arbitrary valuation. They are valuable because they divert our minds from the sheer pointlessness and emptiness of human existence - a condition that lies at the logical endpoint of Hughes' naturalism.
