His idea has been one of the greatest scientific guides for the past few hundred years and a critical signpost on our journey to discern the underlying structure of the cosmos and the nature of reality.
In our efforts to assess our significance, we face a conundrum: Some discoveries and theories suggest life could easily be ordinary and common, and others suggest the opposite.
All indications are that today we also live at an interface or border in time, a transition between a period of stellar and planetary youth and one of encroaching decrepitude.
Our existence in this period of relative calm is, in retrospect, not so surprising.
Put all these factors together, and it is clear that our view of our inner and outer cosmos is highly constrained. Indeed, our basic intuition for random events and our scientific development of statistical inference might have been different under other circumstances of order or disorder, space and time.
And the very fact that we are far isolated from any other life in the cosmos—to the extent that we have not spotted or stumbled across it yet—profoundly impacts the conclusions we can draw.And in grand cosmological terms, only six billion or five billion years ago the universe was decelerating from the big bang. Dark energy, stemming from the vacuum itself, is accelerating the growth of space, helping to quash the development of larger cosmic structures.But this means that life is ultimately condemned to a distant future of bleak isolation within an increasingly indecipherable universe.The smallest reproducing bacteria are a couple of hundred-billionths of a meter across; the smallest viruses are 10 times as small as that.The human body is roughly 10 million to 100 million times larger than the simplest life we know of.Our species has sprung into existence within the barest instant of this universe's enormously long span of history, and it looks like there will be an even longer future that may or may not contain us.The quest to try to find our place, to discover our relevance, can seem like a monumental joke.There are organisms on Earth that are physically larger and more massive than we are—just look at whales and trees.Yet we are much closer to the upper limit of scale than we are to the microscopic end of life's spectrum.As with so many other aspects of our circumstances, we live in a temperate place, not too hot or cold, not too chemically caustic or chemically inert, neither too unsettled nor too unchanging.It is also now apparent that this astrophysically calm neighborhood extends well beyond our local galaxy.