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fields, and our best explanation of why ‘particles’ have mass is the existence of an all-pervading Higgs field. On the other hand, the current evidence only supports the existence of the particle-like aspect of this field: the Higgs boson. The field itself has not been observed. It might not exist, and that would be interesting, because it would overturn the way physicists currently think about particles and fields. It would also be somewhat annoying.
    In everyday life, we encounter solid, compact objects, such as rocks, and they make it easy for us to think about tiny particles. We encounter sloshy but well-defined structures that move around on water, and we feel comfortable with waves. In a human-centred view, there are no sloshy rocks, which makes us assume – almost without questioning it – that nothing can be both particle and wave at the same time. But universe-centred thinking has shown that this assumption can be wrong outside the human domain.
    The human-centred view is as old as humanity itself. It seems to be the default pattern of thinking for most of us, and that makes sound evolutionary sense. The universe-centred view appeared more recently. In the sense that we’re thinking of – science and the scientific method – universe-centred thinking has become widespread only in the last three or four hundred years. It is still a minority view, but a very influential one. To see why, we must understand two things: how science goes about its business, and what constitutes scientific evidence.
    For those of us who are willing to pay attention, the universe-centred view has revealed just how big, how ancient, and how awe-inspiring the universe is. Even on a human scale, it’s a very impressive place, but our parochial perceptions pale into insignificance when confronted by the mind-numbing reality.
    When early humans roamed the plains of Africa, the world must have
seemed
huge, but it was actually extremely small. A big distance was what you could walk in a month. An individual’s experience of the world was limited to the immediate region in which he or she lived. For most purposes, a human-centred view works very well for such a small world. The important plants and animals – the ones useful to specific groups of humans – were relatively few in number, and located in their immediate vicinity. One person could encompass them all, learn their names, know how to milk a goat or to make a roof from palm fronds. The deeper message of the Egyptian hieroglyphs is not how diverse that culture’s flora and fauna were, but how narrowly its symbolism was tailored to the organisms that were important to everyday Egyptian life.
    As we came to understand our world more deeply, and asked new questions, comfortable answers in terms that we could intuitively understand began to make less and less sense. Conceivably the Sun might, metaphorically, be pushed around by an invisible giant dung-beetle, but the Sun is a vast ball of very hot gas and no ordinarybeetle could survive the heat. You either fix things up by attributing supernatural powers to your beetle, or you accept that a beetle can’t hack it. You then have to accept that the motion of the Sun occurs for reasons that differ significantly from the purposeful shoving of a beetle storing up food for its larvae, raising the interesting question ‘why or how
does
it move?’. Similarly, although the setting Sun looks as if it is disappearing underground, you can come to understand that it is being obscured by the rotating bulk of the Earth. Instead of telling a story that offers little real insight, you’ve learned something new about the world.
    It took time for humanity to realise all this, because our planet is far larger than a village. If you walked 40 kilometres every day it would take you three years to travel all the way round the world, ignoring ocean crossings and other obstacles. The Moon is nearly ten times as far away; the Sun is 390 times as far away