So, I’ve now had my fifteen minutes of fame. I’m sure some of you will have read the article about my trip to Germany in The Waikato Times. I have to say that I was quite glad that the reporter (Annette Taylor) kindly left out a remark I made to her during the interview where I said something like "All biology is physics". These kind of statements, though in one sense true (as I’ll explain), are not generally very helpful, and probably do nothing except make physicists (which means me) look completely out of touch with the real world. Which I hope I’m not.
Anyway, enough waffle, this is what I mean by "All Biology is Physics"
School child: Sir, why are plants green?
Teacher: Because they contain chlorophyll which allows them to photosynthesize to provide their energy. [The Biology].
School child: But how does chorophyll make something green?
Teacher: Ahh, it’s the fact that the chlorophyll molecule can absorb photons only at only certain frequencies. [All Biology is Chemistry]
School child: But why does it absorb those photons?
Teacher: Because of the quantum mechanical resonances between the electrons in the molecule and the photons. [All Chemistry is Physics]
So there you go. Ask enough questions, and it gets down to physics in the end. But such a belligerent approach isn’t necessarily helpful. If you go deep enough, it generally gets down to particle physics, which means the way that things like protons, electrons, neutrons and photons interact. Of course, you may then reasonably wonder what on earth the fine structure constant of physics has to do with the colour of trees, and the honest answer would have to be very little. We’ve gone into too much detail. This is why we need physics, chemistry and biology, and their associated offshoots, in all their complexity, to describe the world.
To summarise, the world is a collection of subatomic particles. But it isn’t nothing but a collection of subatomic particles. Long live biology. (Yes, really).