1st, March 2008.
Dear professor Al-Khalili,
ON THE PARADOX OF THE QUANTUM WORLD
I watched your BBC series The Atom.
I want to deal with an important question you raised, where your opinion differs from some of your colleagues, other physicists. As one of them put it, "shut up and calculate," a view with which you disagreed.
So what should one do when the maths reveal an incomprehensible quantum world? Shut up or try to comprehend?
Let me put a different perspective on this question: Is the human brain capable of a rational understanding of the seeming absurdities of the quantum world?
If you took some very intelligent people, like your fellow physicists, and you suggested to them they should take up dance or oil painting, they might reply, "Perhaps one day, as a hobby, but I have no particular talent for either." In other words, they feel their brain is not innately inclined towards physically interpreting music or drawing pictures, let alone performing Swan Lake on stage or producing a Michelangelo. Popular phrases include, "I have two left feet," or "I can't draw a straight line." And we all know what they mean: something in their own head tells them that, no matter how much training and education, they have no natural ability for it, and they never had the urge to go in that direction. Whereas someone else might say "I would have loved to do that, always wanted to, my whole life," or they might feel the urge even now, in adult life, to get up and dance every time they hear music, without ever having had a single dance lesson.
Let's articulate precisely what this means: It means that intelligence does not come simply in quantity, but it takes a very particular form, from birth. Ways of thinking and ways of seeing the world are hard-wired in our brains, just like a gift for music, or indeed blue eyes or curly hair are imbedded in our bodies' DNA.
Yet, although people generally recognise you need to have inborn talent for the arts, they fail to understand that the same applies to science, or anything else, for that matter.
In fact, the reality is far more complex. It is not just that you have, say, musical ability but this in itself can take many different forms, each one unique and genetically determined. Some find playing an instrument comes naturally to them, others, equally musical, find playing difficult, even though their interpretation is as great. Playing involves a particular physical facility (involving the cerebellum, often called muscle-memory, in common parlance) which is different from understanding what needs to be expressed. Similarly, one may have a good voice but no gift for singing. Another may be incredibly shrewd when analysing a piece of music but could never master the violin above a certain level. And great dancers must have a profound appreciation of music in order to interpret it with movement, but they do not make great musicians - and great musicians cannot dance.
This bend of the mind goes beyond knowledge, study or expertise. It is hardwired in the way this particular brain works. Indeed, some are gifted at maths but cannot understand how money works or how to use it, and could never run a business or even their own finances without making a mess. I know such people personally.
Exceptions to this rule are rare, and certain unique individuals are gifted in more than one way, but even then their disparate gifts may overlap in some crucial aspect.
To summarise, it is wrong to think that anyone can attempt to understand a particular question just as long as they have knowledge and enough 'brainpower.' At a certain level, with certain questions, such as whether to shut up and calculate your quantum equations, they also need something else - a very specific kind of mind.
Before I come back to our original question, I want to give one more illustration of a different kind, involving a group of people. Two and a half thousand years ago in ancient Greece, a genetic phenomenon took place which has never been repeated nor ever will, a far higher incidence of individuals with gifted brains per population than ever before or since. What happened in ancient Greece was unique. They surpassed every aspect of human civilisation, to the extent that we still look up to their philosophers, artists, writers, mathematicians, and still study their politics, music and architecture. As scientists, we cannot attribute something like this to the Mediterranean climate, which was shared by many others, or to state education; none of those people had been to university to do a PhD and become 'qualified', nor did they have the technology we do to understand the world. And we do recognise it is way beyond coincidence that all that could have been achieved by such a small group of people, in a small place, in such a very short space of time, in such divergent fields of human endeavour. What did the Greeks have as a group to enable them to crack them all, if it was not something very different in their genes? Just as someone today may have been born with a unique musical talent, what the Greeks, as a group, had got from their genes was a very particular way of creative thinking, the ability to see the essence of the thing with astonishing clarity. So, just like people in Scotland gradually developed more pale skin and a greater number of redheads involving a number of genes, Greece too was a genetic phenomenon due to the smallness of this mountainous country and the isolation imposed by their language, their genetic makeup then compounded by intermarriage.
So we have given two very different examples, one of gifted individuals, the other a group of gifted people, both of which examples illustrate how different ways of thinking are hardwired in the human brain, from birth.
The only thing the Greeks did not discover was the scientific explanation for their own uniqueness - they did not know about the mixing of genes or DNA.
I now move a step closer to our original question, should we just 'shut up and calculate,' or should we try to understand the quantum world?
The apparent complexity and absurdity of the quantum world is not unique in our universe. We are surrounded by, and indeed consist of, such paradoxes. To give a simple example, we knew that NO was a toxic gas that can kill, but a few years back we were astonished to discover that our bodies actually produce NO. The difference is that we do not pose the same question of comprehension as we do about the quantum world. We study how NO is used by our bodies, and once we find the answer, we are satisfied. Indeed, this is the limit of science; anything beyond that may not be unscientific but may be non-scientific. You could ask, 'Couldn't the body achieve the same goal by other means?' And the answer is 'Shut up and give the patient the antidote to NO because he is producing too much and will die any minute now.'
And I could give other examples: When the first reports of the Australian
duck-billed platypus reached Europe, some dismissed it as a hoax. 
There
was no way such an animal could exist, with such disparate body parts,
as well as being a mammal that lays eggs. But once they saw it alive,
they did not pursue the question of its absurdity. They now knew it was
true, they had experienced it with their five senses, so they left it
at that. Description took the place of explanation.
So, the complexity and apparent absurdity we see at sub-atomic level is mirrored in biology, in our eco-systems and elsewhere, but we do not try to comprehend it beyond a certain scientific level. Unlike the ancient Greeks, we make a distinction between science and philosophy. The narrow definition of something as 'scientific' is useful to an extent, but very misleading in other ways. And the reason is that we can see the biological and eco worlds with our senses, and thus become persuaded to 'shut up.' There it is, before your very eyes. Whereas the quantum world remains unseen by our five senses. It is not part of our every day experience, so it is much more difficult to swallow.
If such questions are not scientific, are they of another legitimate kind? Because I certainly want to comprehend the nature of the quantum world, like you do.
What do you think the ancient Greeks would have done? Do you think they would have shut up, or would they have tried to understand, rationally? I am Greek, so let me tell you. The Greeks had discovered one fundamental truth: There is no difference between practical and theoretical questions, no difference between the abstract and the applied. There is only truth or the absence of, and we can use a number of tools to pursue it.
Perhaps the comprehension you and I are after lies, not in maths, but with philosophy. Greek philosophy was, of course, the umbrella under which both maths and the sciences developed in ancient Greece. I see it as a kind of darts-board. In the middle there is bull's-eye, ultimate truth. But then around it, the board of knowledge and understanding is divided artificially, into science, art, politics, etc., in turn subdivided into physics and chemistry, dance and literature, legislating or governing. But all of these touch and meet on bull's-eye at the centre. And if you could see the centre (the essence of things) like the Greeks could, and also have the right kind of brain as an individual, you could crack any question of this kind.
So it would be wrong to dismiss your quantum question as unscientific. It may be non-scientific in terms of science as a modern method of measuring and calculating, but certainly not unscientific - it does not mean it is not valid. You or I may be incapable of dealing with a specific non-scientific question because our brain is hardwired in a particular way, but this only reflects on you or me, not on the question itself.
The long and winding train of thought which started at the top of this letter is leading towards a useful and surprising conclusion: Should we shut up and calculate, or try to understand?
And the answer is this: Your colleague was right. Yes, do shut up and calculate, if that is what your own brain is hardwired to do. But then do bring in a different mind, a different kind of brain, to do the comprehension bit. In other words, you also were right. Trying to comprehend these apparent absurdities is a legitimate pursuit, but you need to bring in a different kind of person to crack this. And I suggest this is exactly the kind of thing the ancient Greek philosophers were uniquely good at.
Einstein, a great admirer of the Greeks and someone who used philosophy on scientific questions, may have been wrong to argue against quantum physics, but he was right to distrust quantum theory. He, like you, had been trying to comprehend, through philosophy, the philosophy of science, as he called it, and he could not, yet, make sense of it. I have come to the conclusion that we are missing some vital link between the quantum world and the everyday world we interact with, as perceived by our senses. Thinking philosophically, there cannot possibly be a contradiction between the two. And we need to use a different brain to tell us what that is, or where to look and how we might find it. Someone with Einstein's philosophical kind of mind will understand first, and the maths will follow later. At this level, insight is closer to artistic creativity than scientific hard graft.
Anyone who fails to grasp this will be caught out. This is the mistake Richard Dawkins makes when arguing for the absence of intelligent design. Whether God exists or not, this is not a matter for science the method, and certainly not for scientists like him, with scientific brains - nor indeed is it a matter for religious minds. What he should do is shut up and calculate. The minute he steps outside the purely scientific - some of his observations are astute, but his logic verges on the ridiculous. He simply does not have the right kind of brain to crack this sort of question.
Who will it be to tell us about the very real quantum world, will it be you or me? Will it be now or a long time in the future?
