This is a re-written version of a piece I wrote some 26 years ago. I was irritated reading the old version by how I didn’t stick to the point. So this version is hopefully more focussed and uses approximately half the number of words of the original.
Fundamental adj. 1. of, involving, or comprising a foundation; basic 2. of, involving or comprising a source; primary [New Collins Dictionary
Is Physics fundamental? As a student I certainly thought that it was, but now – outside of a very narrow domain – I really don’t think it is.
I used to imagine a hierarchy of knowledge with physics underpinning the entire structure. For example, I used to consider that molecular biology was less fundamental than chemistry, and that chemistry was less fundamental than physics. The reason for this is that chemistry, uses concepts like wave-functions and electrons, whereas physics examines these concepts in detail.
My student self would have had a hard time writing down the chain that linked psychology to physics, but he would have believed that chain did existed. And he would certainly not have regarded psychology as fundamental in any sense. I think many physicists still think this way.
But there is another way to look at things. Consider the question “What is Physics?”.
Physicists typically answer the question along the lines of: ‘Physics is the study of the (non-living?) structures in the Universe’. The precise terms of the definition are irrelevant here. What is relevant is that this definition fails to include the fact that physics is an activity performed only by human beings.
Another answer might be ‘Physics is a cultural tradition whose adherents study the (non-living?) structures in the Universe’. In this definition physics lines up with all our other cultural traditions, for example, chemistry, sociology, psychology, English, and even astrology! This definition does not detract from what physics is, but it does allow us to place it in a human context.
I believe that the distinction between these two answers is more than important. because it affects the way that physicists as a community think about ourselves. 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 of our tradition.
For example, consider the physicist’s bête noire: sociology, a subject which is obviously far more fundamental than physics. You disagree? Well ask question ‘What is physics?’ Surely physics is a social activity undertaken by specially trained groups of (mainly) men.
From this sociological viewpoint one can ask questions like ‘Why have structures arisen in society which allow people to study topic X?’ or ‘Which groups dominate the study of of topic X?’. These questions are clearly more fundamental questions than anything to do with the mere content of topic, even X 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.
The key point here is that ‘What is fundamental?’ depends on context.
In short, 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.