Seeing Further: The Story of Science and the Royal Society. Bill Bryson

WE HAVE YET COME TO TERMS WITH THE CHANGE.

      STARSHIP DREAMING

      The Starship Enterprise heads into the void, its warp drive set to maximum, its crew primed ‘to boldly go where no man has gone before’. The drive engages, a burst of light flares out from the rear engines and with an indefinable Woosh ingrained in the minds of Star Trek fans everywhere, the world’s most famous spaceship disappears from our screens and zaps across the universe to a far distant galaxy. As one of those besotted millions, I am not here to quibble about the scientific ‘errors’ in Gene Roddenberry’s masterpiece; as far as I’m concerned ‘Beam me up, Scotty’ remains the most thrilling line on television. What I wish to discuss here is an underlying premise of the series that has tugged at the back of my consciousness since childhood. The crew of the Enterprise take it for granted – as do real-life physicists, astronomers and SETI enthusiasts – that our cosmos is a homogeneous space ruled everywhere by the same physical laws. Such continuity is logically necessary if humans are ever to travel to the stars or communicate extraterrestrially. So essential is the idea of spatial homogeneity to modern science it has been named ‘the cosmological principle’ and it serves as the foundation of our faith that if indeed we are not alone then we will share something meaningful with our alien confrères – the Laws of Nature.

      In the realms of both science fiction and science practice the importance of this principle is hard to overstate, for it underpins physicists’ confidence that the patterns of behaviour discovered here on Earth will govern distant worlds. Apples, planets, stars, galaxies, black holes and the explosive aftermath of the big bang are all compelled by gravity’s unifying force. The Enterprise can set its navigation system to any spatial coordinates precisely because the cosmological principle assures its crew that when they arrive the physics they know and trust will still be working. In contrast to biology, whose plasticity Star Trek writers gleefully celebrate in a myriad polymorphous modes, the laws of physics remain the same everywhere – they are the Platonic ideal at the core of an otherwise capricious cosmos. It is physics that makes ours a uni- rather than a multi-verse.

      To citizens of the twenty-first century the cosmological principle may seem close to tautological. For us space is now an arena to be measured and mapped, ‘the final frontier’ on which we have imposed a metric of parsecs and light years. Yet the idea of spatial continuity was one of the more contentious propositions of the scientific revolution and its consequences have been far reaching. I want to argue here that adopting this view set the stage for an unbearable tension between science and Christianity and has problematised the very concept of a human ‘self’. In essence, concepts of space and concepts of self are inextricably entwined so that when a culture adopts a new conception of space, as Western culture did in the seventeenth century, it impacts our sense of not merely where we are but of what we are. While Newton’s synthesis famously united the heavens and Earth, it tore a hole in our social fabric that we are still struggling to comprehend and whose consequences continue to reverberate in the US ‘war’ between science and religion.

      A SHORT HISTORY OF SPACE

      The magnitude of the transformation taking place in the sixteenth and seventeenth centuries was not lost on any of its participants. Copernicus, Kepler, Descartes, Galileo and Newton all understood that what was at stake in the revolution under way was the fate of the Christian soul. Each of these men stood on the side of God and argued that the emerging cosmology supported a case for the divine. What all of them feared was a universe stripped of spirit. They believed in a Holy Spirit whose Love in-formed the world and in the immanent spirits of their fellow human beings; in ‘the new astronomy’ they saw the reflected glory of their Creator, whose presence in the material universe supported their faith in Christianity’s promise of the soul’s eternal salvation. As Johannes Kepler summed up the case: ‘For a long time I wanted to become a theologian…Now, however, behold how through my effort God is being celebrated in astronomy.’

      The literally soul-destroying potential of the new cosmology hung like a cloud over the consciousness of seventeenth-century science and the source of this angst originated in concerns quite apart from its mechanistic tendencies. By the middle of the sixteenth century thoughtful minds had begun to discern that the idea of continuity between the terrestrial and celestial realms threatened the foundation of Christian faith as it had been construed for 1,500 years. By supplanting the geocentric finitude of medieval cosmology, the new science threatened to undo the metaphysical balance between body and soul on which Christian theology relied.

      Contrary to accounts given in many popular science books, medieval cosmology was underpinned by a rigorous logic that attempted to encompass the totality of humans as physical, psychological and spiritual beings. Medieval scholars read the world in an iconic rather than a literalist sense; nature was a rebus in which everything visible to the eye represented multiple layers of meaning within a grand cosmic order. The physical world was the starting point for investigations that ultimately sought to comprehend a spiritual reality beyond the material plane and what is so beautiful here is that the metaphysical duality of body and soul was mirrored in the architecture of the cosmos.

      As is well known, the medieval cosmos was finite, with the Earth at the centre surrounded by concentric spheres that carried the Sun, the Moon, the planets and stars revolving around us. Beyond the sphere of the stars was the final sphere of the universe proper, what the medievals, following the Greeks, called the primum mobile. Technically this constituted the limit of the universe – here, as Aristotle argued, space and time ended. Critically, because physical space was finite, medieval minds could imagine that ‘beyond’ the material world there was plenty of ‘room’ left for some other kind of space. On medieval cosmological diagrams we see it labelled the ‘Heavenly Empyrean’. What lay ‘beyond’ physical space was the spiritual space of God and the soul.

      In the final stanzas of The Divine Comedy Dante enacts this transition. Having traversed the span of his universe from the depths of Hell in the centre of the Earth, up the purifying mountain of Purgatory and through the celestial layers, Dante pierces the shell of the primum mobile and bursts through the skin of the world to come face to face with God, ‘the Love that moves the Sun and the other stars’. For medieval thinkers this spiritual domain was the primary realm of the Real with the physical realm serving as a secondary and rather pale reflection. Just what it meant to have a ‘place’ outside physical space was a question that much exercised medieval minds – no scholar of the Middle Ages believed that Heaven lay literally beyond the stars. Yet whatever the philosophical difficulties, scholars of the time insisted that physical space was not the totality of reality but one half of a larger metaphysical whole.

      This dualism of body and soul – matter and spirit – was mirrored in a dualism that was believed to exist between the terrestrial and celestial realms. Again, following the Greeks, medieval natural philosophy held that the two regions were qualitatively distinct regions: in the terrestrial realm things were made up from the four mundane elements, earth, air, fire and water; those in the celestial realm (stars, planets, comets and so on) were composed of a fifth element, or quintessence, also known as the æther. Everything in the terrestrial realm was subject to decay and death, those in the heavens were believed to be eternal, prone neither to decay nor change. Subtleties compounded, for the celestial realm was not itself homogeneous. Ascending from the surface of the Earth medieval cosmology posited that in each successive sphere things became more ethereal. In effect, celestial space exhibited a vector of grace: the closer one got to God, the more ‘pure’ the region was said to be. Within the scheme of medieval cosmology, celestial space thus served as a mediating zone between the purely material realm of the Earth and the purely spiritual realm of the Empyrean. To put it another way, the celestial heaven of the planets and stars stood as a metaphor for and pointer to the religious Heaven of God and the soul, and the whole of medieval thinking rejoiced in this analogy.

      But what if terrestrial space and celestial space were not qualitatively distinct? What if the cosmos was a homogeneous domain? Just such an idea began to bubble into European consciousness during the fifteenth century forming the seeds of what would become, in the seventeenth,