Thank goodness today's natural philosophers have their fancy tools at hand when it comes to proving their theories and letting us know just what's what. Imagine the embarrassment of say, Aristotle, were he to be resurrected and held accountable for some of his ideas about the nature of things; notably his belief that the world was composed of four elements — Earth, Air, Fire and Water, as you all well know.
But instead of four, today's natural philosophers tell us that the world is composed of far more 'elements' and elementary particles than you would wish to shake a divining rod at.
So Aristotle was wrong, and if we accept the tenets of that system of thought that is modern physics, we would know that today's touchstones, unlike the old philosopher's sensible, tangible elementals, are hardly conceivable at all.
Up, Down, Top, Bottom, Spin, Charm and Strange
If we wish to grasp the nettle, rather as Aristotle sought to, we must subscribe to a belief that carries its own very peculiar sting. Physics describes a world of interchangeable particles and waves, neither of which appear to obey any common sense rules; nor can we know that an even finer substratum of matter may not be discovered that proves even more elemental than those already hard to imagine pinpricks of charm and strange, up and down, top, bottom and spin.
It is a lot less clear, but we must all surely feel a lot more confident about our present knowledge on the matter, for physics gets tested, does it not? And, before our very eyes, in some occasions. And even if we fail to obtain "the ocular proof" that things work according to that system of "laws", so diligently inscribed by those clerks of nature we call physicists, we just take their word for it, do we not, and much as we always have done.
So, when this or that beam of light turns out to be here or there, doing this or that, just as physics said it would, it would all seem rather incontrovertible.
Until you think once more, strangely enough, of Aristotle's Earth, Air, Fire and Water, that is.
For did he not put his ideas to the test? He surely did, and I suspect that when he predicted that a stone would fall or a flame shoot up, they did just that.
So what is the test? Presumably, for there are few among us, I am sure, who could claim to feel they were in a position to challenge or test physicists' pronouncements on what the world is made of, we just go along with it, oohing and ahhing from time to time.
And if we cannot test a belief, then it is nothing less than an act of trust or even faith that we embark on when we conclude that a particle can be in two places at the same time, just as physicists say it will.
The Moon Is Made Of Green Cheese
Most people are unaware of this quantum leap of faith they must make if they are to accept the findings of physicists, not to mention the tacit accord they give, when applauding the achievements of the electron-scanning microscope or the promise of a "Quantum" computer, to fundamental principles that, were they put to them baldly in terms they might understand, would be scoffed at.
But the odd thing is, is that we trust in these notions not because we feel that charm, strange and spin are palpably, if not intuitively true, as Aristotle's students must have felt his elementals to be, or however unlikely (certainly in my case), because we've done the math, but because we have no practical means of rebutting any of the propositions laid before us.
Let's face it, if NASA scientists were to tell us that the Moon is indeed made of green cheese, there would be few among us who would really gainsay them. And what if they were to let us examine it at close quarters, and it did indeed smell of cheese, what then? And who are you to say that it doesn't smell of cheese? Have you ever smelt moon-rock? Are you ever likely to? On what then do base your assumption that it doesn'tsmell of cheese?
You, the well-informed layman, know practically nothing about these big notions of time and space that can be said to be derived from your own direct experience or observation of how the world works. Sure, a stone drops, and you know that it is not because like seeks like, but because of gravity; but what do you know of gravity? Could you have predicted that the same forces that allow a bicycle to remain upright would bend starlight and suck time and space into itself? And if not, how come?
Is it because you don't understand, any more than anyone is likely to really understand a force that acts at a distance between the objects concerned, without any observable exchange of energy or matter? And even less likely to really understand a force that bends space and time so that nothing can truly be said to be all the same for any of us ever again. If this is true of the ideas of Newton and Einstein, how much more so must it be true of a field of inquiry which, according to one of its greatest practitioners, is almost axiomatically opaque to our reason — Quantum Mechanics?
No matter that it 'works'; no matter that useful answers may be supplied to the usual questions, Quantum Mechanics remains rooted in a world that obeys none of the usual, common sense rules of cause and effect; like the fairies at the bottom of the garden, it cannot be observed without it in some subtle way hiding an aspect of itself from our gaze; that very gaze that we are lead to believe will determine what we see.
Not that this is in itself necessarily important, however thrillingly bizarre it may appear. But if science makes the unimaginable thinkable, is it surprising that there should be a resurgence of the 'merely' imaginative? Physicists throw their arms up in horror at the more fanciful, unscientific notions that people recover from folklore and mythology — not least among which is surely a belief in Earth, Air, Fire and Water.
But until they start tele-transporting matter before our eyes (if only for form's sake), by which measure, I ask, are we to test these propositions, so inimical to our ordinary experience; so mind-bending in their apparent possibilities?
The Secrets of Quantum Physics - Einstein's Nightmare | (BBC Four)
For a more accessible and less technical introduction to this topic, see Introduction to quantum mechanics.
Introduction to Quantum Mechanics
This article is a non-technical introduction to the subject. For the main encyclopedia article, see Quantum mechanics.