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Outside this range even our imagination is handicapped, and we need the help of instruments and of mathematics - which, fortunately, we can learn to deploy.
The range of sizes, distances or speeds with which our imaginations are comfortable is a tiny band, set in the midst of a gigantic range of the possible, from the scale of quantum strangeness at the smaller end to the scale of Einsteinian cosmology at the larger.
Our imaginations are forlornly under-equipped to cope with distances outside the narrow middle range of the ancestrally familiar.
We try to visualize an electron as a tiny ball, in orbit around a larger cluster of balls representing protons and neutrons. That isn't what it is like at all. Electrons are not like little balls. They are not like anything we recognize. It isn't clear that 'like' even means anything when we try to fly too close to reality's further horizons.
Our imaginations are not yet tooled-up to penetrate the neighbourhood of the quantum.
Nothing at that scale behaves in the way matter - as we are evolved to think - ought to behave. Nor can we cope with the behaviour of objects that move at some appreciable fraction of the speed of light. Common sense lets us down, because common sense evolved in a world where nothing moves very fast, and nothing is very small or very large.
The way we see the world, and the reason why we find some things intuitively easy to grasp and others hard, is that our brains are themselves evolved organs: on-board computers, evolved to help us survive in a world - I shall use the name Middle World - where
- the objects that mattered to our survival were neither very large nor very small;
- a world where things either stood still or moved slowly compared with the speed of light; and where the very improbable could safely be treated as impossible.
- Our mental... [sensory] ...window is narrow because it didn't need to be any wider in order to assist our ancestors to survive.
Our brains have evolved to help our bodies find their way around the world on the scale at which those bodies operate.
We never evolved to navigate the world of atoms. If we had, our brains probably would perceive rocks as full of empty space.
Rocks feel hard and impenetrable to our hands because our hands can't penetrate them. The reason they can't penetrate them is unconnected with the sizes and separations of the particles that constitute matter. Instead, it has to do with the force fields that are associated with those widely spaced particles in 'solid' matter.
It is useful for our brains to construct notions like solidity and impenetrability, because such notions help us to navigate our bodies through a world in which objects - which we call solid - cannot occupy the same space as each other.
We have brains that evolved in medium-sized ancestors, who couldn't walk through rocks, so our 'really' is a 'really' in which rocks are solid.
'Really', for an animal, is whatever its brain needs it to be, in order to assist its survival. And because different species live in such different worlds, there will be a troubling variety of 'reallys'.
What we see of the real world is not the unvarnished real world but a model of the real world, regulated and adjusted by sense data - a model that is constructed so that it is useful for dealing with the real world. The nature of that model depends on the kind of animal we are.
- A flying animal needs a different kind of world model from a walking, a climbing or a swimming animal.
- Predators need a different kind of model from prey, even though their worlds necessarily overlap.
- A monkey's brain must have software capable of simulating a three-dimensional maze of branches and trunks.
The general form of the mind model - is an adaptation to the animal's way of life, no less than its wings, legs and tail are...
From the Last Chapter of The God Delusion - Richard Dawkins
