truth consists of such correspondence between theories and physical reality.
Scientists operating giant particle accelerators likewise look at pixels and ink, numbers and graphs, and thereby observe the microscopic reality of subatomic particles like nuclei and quarks. Others operate electron microscopes and fire the beam at cells that are as dead as dodos, having been stained, quick-frozen by liquid nitrogen, and mounted in a vacuum – but they thereby learn what living cells are like. It is a marvellous fact that objects can exist which, when we observe them, accurately take on the appearance and other attributes of other objects that are elsewhere and very differently constituted. Our sensory systems are such objects too, for it is only they that are directly affecting our brains when we perceive anything.
Such instruments are rare and fragile configurations of matter. Press one wrong button on the telescope’s control panel, or code one wrong instruction into its computer, and the whole immensely complex artefact may well revert to revealing nothing other than itself. The same would be true if, instead of making that scientific instrument, you were to assemble those raw materials into almost any other configuration: stare at them, and you would see nothing other than them.
Explanatory theories tell us how to build and operate instruments in exactly the right way to work this miracle. Like conjuring tricks in reverse, such instruments fool our senses into seeing what is really there. Our minds, through the methodological criterion that I mentioned in Chapter 1, conclude that a particular thing is real if and only if it figures in our best explanation of something. Physically, all that has happened is that human beings, on Earth, have dug up raw materials such as iron ore and sand, and have rearranged them – still on Earth – into complex objects such as radio telescopes, computers and display screens, and now, instead of looking at the sky, they look at those objects. They are focusing their eyes on human artefacts that are close enough to touch. But their minds are focused on alien entities and processes, light years away.
Sometimes they are still looking at glowing dots just as their ancestors did – but on computer monitors instead of the sky. Sometimes they are looking at numbers or graphs. But in all cases they are inspecting local phenomena: pixels on a screen, ink on paper, and so on. These things are physically very unlike stars: they are much smaller; they are not dominated by nuclear forces and gravity; they are not capable of transmuting elements or creating life; they have not been there for billions of years. But when astronomers look at them, they see stars.
SUMMARY
It may seem strange that scientific instruments bring us closer to reality when in purely physical terms they only ever separate us further from it. But we observe nothing directly anyway. All observation is theory-laden. Likewise, whenever we make an error, it is an error in the explanation of something. That is why appearances can be deceptive, and it is also why we, and our instruments, can correct for that deceptiveness. The growth of knowledge consists of correcting misconceptions in our theories. Edison said that research is one per cent inspiration and ninety-nine per cent perspiration – but that is misleading, because people can apply creativity even to tasks that computers and other machines do uncreatively. So science is not mindless toil for which rare moments of discovery are the compensation: the toil can be creative, and fun, just as the discovery of new explanations is.
Now, can this creativity – and this fun – continue indefinitely?
3
The Spark
Most ancient accounts of the reality beyond our everyday experience were not only false, they had a radically different character from modern ones: they were anthropocentric. That is to say, they centred on human beings, and more broadly on people – entities with intentions and human-like thoughts – which included powerful, supernatural people such as spirits and gods. So, winter might be attributed to someone’s sadness, harvests to someone’s generosity, natural disasters to someone’s anger, and so on. Such explanations often involved cosmically significant beings caring what humans did, or having intentions about them. This conferred cosmic significance on humans too. Then the geocentric theory placed humans at the physical hub of the universe as well. Those two kinds of anthropocentrism – explanatory and geometrical – made each other more plausible, and, as a result, pre-Enlightenment thinking was more anthropocentric than we can readily imagine nowadays.
A notable exception was