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Everything, for the price of calculus

My wife asked me to write about the practical value of learning physics. Apparently some people believe that physics is an impractical field, that it does not confer economically valuable knowledge. I disagree.

Physics is the quantitative study of reality - and more particularly, the search for universal laws that explain it. When we find a universal law, all of existence, in particular every device ever made and every mind ever born, exists in that reality and so must be subject to it. This of course is incredible, presumptuous, arrogant, ridiculous. Why should such laws exist? It would be a miracle - yet apparently they do, and we have found several. They are not perfect, they are not consistent, they are not complete, but they encompass everything. Can you imagine that? It is the greatest bargain in history: everything, for the price of calculus.

Of course I do not literally mean that calculus is the only mathematics involved in physics (although you could be forgiven for thinking so). I do mean that the subject is universal and this has enormous practical benefits.

Are you interested in earning money? Producing economic value? Creating things that other people will pay you for? Many of those things are made of atoms and photons! All of them, really, except for software and writing. For example:

are all products made of some combination of atoms and light. Do you want to create the next trillion dollar company? Do you simply want to have an interesting and rewarding job that pays well enough to support you and your family? Consider constructing physical goods through knowledge of physics! It will tell you - if coarsely - how those atoms and photons would interact if you put them together in a certain way, and what effect that would have on the product. This lets you figure out which configurations are impossible, which are simply a bad idea, and which have a shot at working, before you go buy all the parts and start putting them together. More importantly, it tells you the best you could possibly do, which lets you maintain very high standards. "Fast" means the speed of light.

Is knowledge of physical law sufficient to construct useful goods? By no means. There is all the difference in the world between understanding how a nuclear reactor or a wrench works and being able to build one. You need engineers with practical expertise making repeated contact with reality to actually make something that functions. Knowledge of physics will not make you a mechanical engineer any more than it will make you a programmer, or a PCB designer, or a pastry chef, but it will give you a model of the way things work sufficient to interact with engineers at low resolution, evaluate their work, and if necessary, learn how to do it yourself.

It is not necessary - plenty of people build new and delightful things without having heard of Newton's laws. No course of study is necessary. I only mean to point out that this particular one has some practical benefit on top of the delight that comes from tasting the distillation of four hundred years of concerted effort from some of the greatest minds in history. The real reason to study physics is the same as it has always been: the joy and awe that comes from peeling back the layers of reality. If that is something that excites you, give it a try. You may find yourself capable of more than you expected.



Thanks to Sanya Timar for reading drafts.