Thomas Moynihan writes:

Do you recall the first time you knew you would die? It’s a milestone, realising your time is limited. That things happened before you, and will happen afterward, in your absence.

As we grow up, the understanding of death comes in stages, but it culminates in acknowledgment of one’s own – unavoidable yet unpredictable – mortality. Sometime between the ages of six and 10, children become aware that their time is inescapably bounded.

Roughly the same might be said of humanity’s self-knowledge. Only recently has the human collective begun accepting the fact it is itself mortal. We now appreciate that events unfolded for aeons before us and that our species can disappear, never to return. One day, the cosmos will persist without human witness, nor any inherent tendency to manifest things we cherish.

The anti-war campaigner Jonathan Schell called this realisation the ‘second death’. Growing up, each of us comes to terms, psychologically, with a ‘first death’ – our own – but, beyond this, lurks the realisation that humankind itself hasn’t always existed and won’t be around forever.

For most of history, such understanding was lacking. People could defang – or outright deny – the possibility of beginnings and ends greater than those of our own biographies by appealing to eternity. Before we found evidence to prove otherwise, it was permissible to presume that, beyond tangible scales, time has no true bounds. For millennia, people have found comfort in this, because nothing dies in eternity. Given eternal time, every possibility – no matter how wildly improbable – will repeat and recur limitlessly. Outside our island of perceptible time – within eternity’s boundless ocean – it remained plausible to assume that all deceased things will eventually resurrect.

It’s now clear humanity lacks the luxury of eternity. We know this because evidence has accumulated to show that there are greater, even more encompassing mortalities than our own. We now understand Earth and its life had their origins and, one day, they will be cremated by our ageing Sun. A ‘third death’, then. Beyond that, even the Universe itself has its bounds: it began with a bang, and the consensus view is that, in the distant future, it will likely have its end. Thus, a ‘fourth death’. Multiple grander mortalities, expanding concentrically outward.

We are only just coming to terms with this – this supremacy of finitude. It marks a historic reorganisation of our sense of orientation that may, one day, be judged comparable to that of the Copernican Revolution. Just under 500 years ago, Nicolaus Copernicus initiated a string of discoveries eventually proving our planet is not the centre of a tidy, manageable cosmos. Instead, Earth pirouettes around a mediocre star within an ungraspably vast Universe. It took generations for people to start noticing – and giving names to – what Copernicus had wrought. Similarly, we are only now waking up to the significance of the nested mortalities we live within. With the most seismic revolutions, it takes time for the dust to settle before we can glimpse the landscape transformed.

However, whereas Copernicus made us feel insignificant in space, placing bookends on time stands set to reverse this, by insinuating that our acts might just be more cosmically resonant than we previously dared presume. One revolution, undone by another.

Why? I argue that abandoning eternity is ultimately galvanising: for it implies that what we do in our moment on Earth genuinely matters beyond our own fleeting lives. Only by finding time’s cosmic bookends has modern science thrown into crisp relief the truth that what happens next might resonate indelibly. Because, if time has extremities, then history will never repeat; and if what’s happening here and now will never reoccur, certain decisions can never be taken back or reversed. [Continue reading…]