In his almost penetrable work An Inquiry into Meaning and Truth, Bertrand Russell argued along the following lines: commonsense leads to physics, physics falsifies commonsense, since commonsense thus undermines itself, it cannot be true. Why does commonsense lead to physics? Well, part of commonsense – at least as Russell understood the term – is that when we see the world, we are confronted with a reality that is distinct and independent of the fact that we do see it, and that reality is filled with solid, coloured and variously shaped objects – the chair you are sitting on for instance. Because we are by nature inquisitive creatures, we then start asking questions about the nature of these things we see, and in attempting to answer them, we start doing physics (and possibly metaphysics as well). So, why does physics undermine commonsense? Well, taken equally realistically, modern physics – which sits at the tail end of a long history of intellectual pursuit – tells us that our external world is made up largely of a vast void, peppered with entities so small that notions of solidity, colour and even shape make no sense when applied to them, other than perhaps metaphorically. Since for Russell, and many, many, many other people, physics should be interpreted realistically, it follows that physics tells us that – contrary to commonsense – our external world is not full of solid, colourful things.
In fact, what Russell’s argument actually shows is that we face a choice: either we can be realists about modern physics, and ditch commonsense or we can regard the deliverances of modern physics merely instrumentally. This would involve treating the fundamental laws of the universe only as tools for manipulating the real world of commonsense, and not as statements about what reality actually consists in. I want to stick an oar in for this alternative.
Imagine we take physics realistically, and suppose that the world is really populated by fermions and bosons so small and strange that shape, colour and solidity make no sense when applied to them. One question this raises is what is the relationship supposed to be between those fundamental particles and the common-or-garden objects of commonsense, such as snooker balls, cafés, even human bodies? If you look at physics text books, even very advanced ones, the underlying assumption is that the latter things are just made up out of the former. But this won’t work of course, since add as many billions of colourless things together as you like into a big bundle, because they are all colourless, so will the resulting bundle. So if your left hand is made up of billions of billions of colourless quarks and electrons, it should be colourless itself, yet there it is in front of you in all its pink, or brown, or greenish blue splendor. “But don’t be so naïve,” I hear the modern physicists amongst your baying “of course it’s not the case that the macroscopic objects of commonsense are made up of electrons and quarks etc. The story is much more sophisticated than that. Out there in the real world are just fermions, bosons and the void as physics tells us, a world where colour, shape and solidity really have no place. However, some of those bosons, we call them photons, interact with other particles then enter into our eyes and stimulate our brains, and this results in our having experiences of a world of coloured, shaped and solid things. So, the perceived world is, if you like, partly a product of our minds – or, if you prefer, something we project onto the real world.” You may have come across this kind of suggestion before – I once heard the great physicist Richard Feynman going through a similar kind of spiel. Well, sorry to disappoint you, but the whole story is based on a contradiction, and since contradictions cannot be true, neither can the story itself.
Compare the sentence with which the story kicks off – “out there in the real world are just fermions and bosons” – with the phrase that presents part of the conclusion of the tale – “the perceived world is a product of our minds”. In understanding the first sentence, you understand the subordinate clause “out there in the real world”. From where did you obtain your understanding of that phrase? Leaving aside the grasp we have of linguistic structure, which according to some is innate, your understanding of the substance of language – the meaning of words – is garnered from acting in, being guided through, and perceiving the world, i.e. the perceptible world. That being the case, your notions of the real world and the perceived world are inextricably interweaved. Consequently “out there in the real world are just fermions and bosons” means at least “out there in the perceptible world are just fermions and bosons”. However, according to the second phrase I highlighted, the perceptible world is supposed to be a mind-dependent construction brought into being by the effects of light on sentient beings. So, on the one hand fermions and bosons must exist independently of the perceptible world, in order to participate in causing that world’s coming into existence, yet on the other hand they are supposed also to be things that exist in that perceptible world, and so cannot be independent of it. The story spun by some modern physicists, then, boils down to the contradiction that fundamental particles, or waves of energy or whatever, both are and are not independent of the perceptible world, and there lies the contradiction. Despite what some French philosophers might say, it is a rule of reason as basic as they come that contradictions cannot be true, so the story being fed us by those who want to interpret modern physics realistically, is contaminated not only by muddle-headedness, but more importantly by falsehood.