While searching on the internet, I came across an article I wrote in 1990 called Physics is not fundamental.
I wouldn’t quite agree with everything my 30 year-old self wrote, but I don’t disagree with much of it.
Anyway, for good or bad, here it is: all 1350 words – more than twice as long as normal blog post: sorry.
In between lectures, I was discussing with one of my students the reasons why he was studying physics. The student pointed to the cost of attending the course, and the extra costs involved in terms of time, books and travel, and said that if he considered it in terms of the cost of the course and the likely financial rewards, then he wouldn’t bother. He then said that the key thing about physics that made it all worthwhile was that it was fundamental. And that set me thinking . . .
I had in fact been thinking about this particular question for a long time: ‘Is physics fundamental?’. I recalled that as a student I had certainly thought that it was, but I realised that now I didn’t really believe that anymore. What had happened?
As a physics student I believed that physics was the most fundamental study one could undertake. I recall that I looked down on engineers with their apparently endless parametrisation. I recall being mystified at how someone could study English for three years! I could not conceive of how anyone could really want to study something other than physics.
My attraction to physics had grown from my teenage interest in answering the questions we all ask. ‘What is going on here?’, and ‘Why is it going on?’. I side-stepped the philosophers’ stumbling block of trying to find out whether or not I existed, and physics (or natural philosophy, as I still like to call it) was where I ended up. With the minimal assumption that both oneself and the world existed, physics seemed to supply very solid answers to my questions. However, the type of questions I asked then differ from those I ask now.
Now I have learned to ask directly solvable questions such as ‘What voltage should I expect at my pick-up coil?’. And slowly (very slowly) I have learned to answer these questions. This process is still a joy to me. However, aside from learning about these technical matters, my questioning has gone on, and I have come to think that physics doesn’t really supply very solid answers after all. In particular, I have come to the view that only in a very limited sense can physics be considered fundamental. My dictionary describes fundamental as:
Fundamental adj. 1. of, involving, or comprising a foundation; basic 2. of, involving or comprising a source; primary [New Collins Dictionary]
and it is in the sense of referring to a foundation that I use the word. I think the image that my student had in mind when he used the word fundamental was of a hierarchy of knowledge with physics underpinning the entire structure.
For example, molecular biology would be seen as less fundamental than chemistry, and chemistry would be seen as less fundamental than physics. The reason for this chain is that chemistry, for example, uses concepts like wavefunctions and electrons, whereas physics examines these concepts in some detail. Physics then in some sense underlies chemistry and thus molecular biology. My student would have had a hard time writing down the chain that linked psychology to physics, but he would have believed it existed, and would certainly not have regarded psychology as fundamental. This reductionist approach may be aptly referred to as Lego philosophy. It is my belief that a number of physicists subscribe to some version of this philosophy, and it is my aim in this article to show that there is another way to look at things.
This other way to look at things starts with the question ‘What is physics?’. The Lego philosophers answer this question with something along the lines of: ‘Physics is an attempt to study/describe the (non-living?) structure/matter in the Universe’. The precise terms of the definition are irrelevant in this argument. What is relevant is that this definition fails to include the fact that physics is an activity performed only by human beings. The physics found in books is just a part of a cultural heritage that is held in the minds of people like you and me. We are it! I would put forward another definition of physics which would start: ‘Physics is a cultural tradition whose adherents attempt to study /describe . . .’.In this definition physics lines up with all our other cultural traditions, for example, chemistry, sociology, psychology, astrology, and even English! It is a valuable tradition. No more. No less. This definition does not detract from what physics is, it merely allows us to place it in its proper context.
I believe that the distinction between these two definitions is more than pedantry. It affects the way that as a community we think of ourselves. It affects the kind of people who might want to become physicists. And it affects the way we try to communicate to students and colleagues, the special skills and ways of looking at the world that are at the heart our tradition.
Let me give a couple of examples of what I’m trying to get at.
First, consider sociology, a subject which is obviously far more fundamental than physics. You disagree? Well think about it for a while: take a look around and gather some data: What is physics? I think there are two types of answers corresponding to the two definitions I gave above. One might say physics is the keystone of a pyramid of ‘knowledge’, or that physics is an activity undertaken by specially trained groups of (mainly) men. Both answers are equally valid in their own terms.
If one takes the first view then nothing can be more fundamental than physics: ‘Everything else is stamp collecting‘.
But if one takes the second view, one is able to appreciate that different things are fundamental in different contexts. From this viewpoint one can see that questions like ‘Why have structures arisen in society which allow people to study topic X?’, are more fundamental questions than anything to do with the mere content of topic X, even where X = physics. One can construct similar questions involving just about any study. For example, since we communicate our thoughts using languages, it is particularly striking that linguistics and neurophysiology are ‘more fundamental’ than anything which is merely the content of thoughts or languages.
Secondly, let me highlight what a shift of emphasis in our definition of ‘What physics is‘ might achieve by considering my own area of work as a university lecturer. I believe that the standard of physics education at universities is appalling. One of the reasons it is so bad is that physics lecturers have failed to appreciate what it is they are doing when they give a lecture. They have failed to appreciate that physics is not a syllabus and is not contained in the ‘content’ of a lecture. It is an activity, and students are learning the social norms of that activity. Such norms include the asking of questions if you understand what is being taught, and not asking questions if you don’t! Is it really possible that rational human beings could have established such norms in an educational establishment?
If physicists could recognise that what we have is a valuable cultural tradition, then maybe we could get around to realising that the most fundamental thing about a lecture is not its ‘content’, but the establishment of norms that allow and indeed encourage students to discuss what they don’t understand. In this context psychology is more fundamental than physics.
To summarise, it is my belief that it is important to acknowledge that physics is an activity performed only by human beings and so human beings are central, and not peripheral, to the description physics gives of the world. The prize to be won by such a collective change of mindset is a reinvigoration of the community of physicists, making it a more welcoming group for people to want to belong to.