The 18th-century German philosopher Immanuel Kant wrote: "Two things fill the heart with ever renewed and increasing awe and reverence, the more often and more steadily we meditate upon them: the starry firmament above and the moral law within."
This year, the 400th anniversary of Galileo's first use of a telescope, has been declared the International Year of Astronomy, so this seems a good time to ponder Kant's first source of "awe and reverence". Indeed, the goal of the commemoration – to help the world's citizens "rediscover their place in the universe" – now has the incidental benefit of distracting us from nasty things nearer to home, like swine flu and the global financial crisis. So, what does astronomy tell us about "the starry firmament above"?
By expanding our grasp of the vastness of the universe, science has, if anything, increased the awe and reverence we feel when we look up on a starry night (assuming, that is, that we have got far enough away from air pollution and excessive street lighting to see the stars properly). But, at the same time, our greater knowledge surely forces us to acknowledge that our place in the universe is not particularly significant.
In his essay, Dreams and Facts, the philosopher Bertrand Russell wrote that our entire galaxy is a tiny fragment of the universe, and within this fragment our solar system is "an infinitesimal speck," and within this speck "our planet is a microscopic dot."
Today, we don't need to rely on such verbal descriptions of our planet's insignificance. The astronomer Carl Sagan suggested that the Voyager space probe capture an image of earth as it reached the outer reaches of our solar system. It did so, in 1990, and Earth shows up in a grainy image as a pale blue dot. If you go to YouTube and search for "Carl Sagan – pale blue dot" you can see it, and hear Sagan himself telling us that we must cherish our world because everything humans have ever valued exists only on that pale blue dot. That is a moving experience, but what should we learn from it?
Russell sometimes wrote as if the fact that we are a mere speck in a vast universe showed that we don't really matter all that much: "On this dot, tiny lumps of impure carbon and water, of complicated structure, with somewhat unusual physical and chemical properties, crawl about for a few years, until they are dissolved again into the elements of which they are compounded."
But no such nihilistic view of our existence follows from the size of our planetary home, and Russell himself was no nihilist. He thought that it was important to confront the fact of our insignificant place in the universe, because he did not want us to live under the illusory comfort of a belief that somehow the world had been created for our sake, and that we are under the benevolent care of an all-powerful creator. Dreams and Facts concludes with these stirring words: "No man is liberated from fear who dare not see his place in the world as it is; no man can achieve the greatness of which he is capable until he has allowed himself to see his own littleness."
After the second world war, when the world was divided into nuclear-armed camps threatening each other with mutual destruction, Russell did not take the view that our insignificance, when considered against the vastness of the universe, meant that the end of life on Earth did not matter. On the contrary, he made nuclear disarmament the chief focus of his political activity for the remainder of his life.
Sagan took a similar view. While seeing the Earth as a whole diminishes the importance of divisions such as national boundaries, he said, it also "underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known". Al Gore used the "pale blue dot" image at the end of his film, An Inconvenient Truth, suggesting that if we wreck this planet, we have nowhere else to go.
That's probably true, even though scientists are now discovering other planets outside our solar system. Perhaps one day we will find that we are not the only intelligent beings in the universe, and perhaps we will be able to discuss issues of inter-species ethics with such beings.
This brings us back to Kant's other object of reverence and awe, the moral law within. What would beings with a completely different evolutionary origin from us – perhaps not even carbon-based life forms – think of our moral law?
Copyright: Project Syndicate, 2009
Pale Blue Dot
--by Carl Sagan (Jan 25, 2010)
Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there -- on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.
Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.
The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.
It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.
--Carl Sagan, Pale Blue Dot, 1994