Martin J. Rees on ’theory of everything’ and perspectives on cosmology
“Our Galaxy is itself just one of many billion galaxies in range of our telescopes. And there is compelling evidence that this entire panorama emerged from a hot, dense ‘beginning’ nearly 14 billion years ago. (…)
The vast domain that astronomers can observe could be an infinitesimal part of the totality. Our big bang may not be the only one: we may be living in a ‘multiverse’ – an archipelago of cosmoses, perhaps governed by an array of different physical laws.
The bedrock nature of space and time, and the unification of cosmos and quantum are surely among science’s great ‘open frontiers’. (…)
But to call this a quest for the ‘theory of everything’ is hubristic and misleading. Biologists and environmental scientists (and even most physical scientists) aren’t held up at all by the lack of such a theory – they are tackling a third frontier: the very complex. (…)
It may seem incongruous that scientists can make confident statements about galaxies billions of light years away, while being baffled about issues close at hand that we all care about – diet and common diseases, for instance. But this is because living things with intricate levels of structure (even the smallest insects) are far more complex than atoms and stars. (…)
But even if those equations could be solved, they wouldn’t offer the enlightenment that scientists seek. Each science has its own autonomous concepts and laws. Reductionism is true in a sense. But it’s seldom true in a useful sense. Problems in biology, and in environmental and human sciences, remain unsolved because it’s hard to elucidate their complexities – not because we don’t understand subatomic physics well enough.
Along with the origin of the physical universe, the beginnings of life surely pose another ‘big question’. (…) Our cosmos would then seem far more interesting: we would look at a distant star with renewed interest if we knew it was another Sun, shining on a world as intricate and complex as our own.
We may learn this century whether biological evolution is unique to the ‘pale blue dot’ in the cosmos that is our home, or whether Darwin’s writ runs through a wider universe that teems with life – even with intelligence.
Are there special perspectives that cosmologists can offer to philosophy? I think there are. First, their findings disclose the interconnectedness of cosmic processes. Not only do humans share a common origin with the entire web of life on Earth, but all living things depend on the stars: life is energised by heat and light from the Sun; we are made of atoms that were forged from pristine hydrogen, in faraway stars long ago. To understand ourselves we must understand the atoms we’re made of – and the intricate complexity with which they combine into DNA, proteins and cells. But we must also understand the stars in which those atoms were made.
But cosmologists offer another distinctive insight: an awareness not only of the immensity of space but of the ‘deep time’ that lies ahead. The stupendous timespans of the evolutionary past are now part of common culture. But most people still somehow think we humans are the culmination of the evolutionary tree – and that hardly seems credible to an astronomer. Our Sun formed 4.5 billion years ago, but it’s got 6 billion more before the fuel runs out. According to the best current ultra-long-range forecast, the expanding universe will continue – perhaps until infinity – becoming ever colder, ever emptier. So, even if life were now unique to Earth, there would be abundant scope for posthuman evolution on the Earth or far beyond. It won’t be humans who witness the Sun’s demise: it will be entities as different from us as we are from a bug – either organic or siliconbased. (…)
My concerns are deepened by the realisation that, even in a perspective extending billions of years into the future, as well as into the past, this century may be a defining moment. Our planet has existed for 45 million centuries, but this is the first in its history where one species – ours – has Earth’s future in its hands, and could jeopardise not only itself, but life’s immense potential.”