Theoretical vs. Experimental

From Jonathan Gardner's Physics Notebook
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After much soul-searching, I discovered I am really an experimental physicist. As such, I don't appreciate the way theoretical physicists work. So my comments toward them are slightly less than they deserve.


There are two approaches to physics. Although, to outsiders, they seem similar, in reality, it is a deep divide that has created two communities almost at war with each other.

What is Theoretical Physics?

Theoretical physics is the kind of physics that Einstein did. He would think of things, and then do the math, and find out interesting formula and patterns, and new ways to describe old things. Occasionally, theoretical physicists will predict something new, and even more rarely, they will predict something new that isn't garbage.

Einstein and Feynman are two great examples of theoretical physicists.

What is Experimental Physics?

The experimental physicist is someone who has no opinion about how the universe should work. He believes that if he can simply measure the universe, he can uncover interesting patterns and ideas. He believes that all theories must start and end with experimental data. Any other kind of theory work is pointless and a waste of time.

Don't get me wrong: Experimental Physicists are often just as bright and even brighter than theoretical physicists. However, they spend the majority of their brainpower figuring out how to coax new results out of nature, which is very difficult given the constraints of technology and limited resources.

Famous experimental physicists include Rutherford and the work done at CERN. Experimental physicists, of necessity, tend to work on teams so individuals don't stick out as much as their teams do.

Why the divide?

The divide can be explained thusly.

Theoretical physicists see experimental physicists and wonder why they are wasting their time on machines and gadgets. They wonder why they don't take more time to pontificate on the obvious symmetries and math underlying their work.

Experimental physicists, on the other hand, look at theoretical physicists and wonder what they intend to uncover with all their thinking about things that don't matter. What does it matter that you can take 4 numbers and arrange them in a line or in a matrix or twist them? In the end, math is a tool no different from a hammer or a computer. You use it to calculate numbers, numbers that reflect the way reality is, or is predicted to be, numbers that you can verify with experiment.

Theoretical Physicists put the human mind above all else, our ability to imagine and reason and think.

Experimental Physicists put the universe above all else. The universe has a lot to tell us, if we'll simply look and listen.

Why You Do Not Want to be a Theoretical Physicist

I know a lot of people, myself included, imagined being an Einstein. We'd get the great insight that shifts the fundamental understanding of the universe.

That's a load of garbage. Einstein did nothing of the sort. What he did was he explained why experimental results were disagreeing with prevailing theory. Then he spent the rest of his life on a mad goose hunt.

Let me help you understand why. Let's say I give you the number "4", or rather "4 meters". OK, what can you do? Well. 4 meters is 400 cm is 0.004 km and so on. It takes light a certain amount of time to travel 4 meters. A ball that falls from rest 4 meters will accelerate to such-and-such a speed and will take so long to get there. All of these are fascinating and interesting. But they are all useless.

See, I wanted 4 meters to be the width of a room I am building. What does it matter about all of the above? Who cares?

In the end, theoretical physicists just rearrange the deck chairs. They invent new notations, new ways of seeing things, but these have absolutely no bearing on reality. Reality doesn't care what you think or why you think it. It has its own ideas, and we are barely scratching the surface of what it can tell us.

Occasionally, and I do mean occasionally, a theoretical physicist figures something out that is actually useful. We pat them on the back, test out their ideas, and move on.

String Theory

The problem with theoretical physicists today is that they are all interested in string theory. String theory is problematic because it's not testable. They're pontificating on things where they can make up whatever they want and no one can check to see if they are right.

Experimental physicists understand the popularity of string theory, but under muttered breath, they will sigh that there is nothing to test, nothing to do. Meanwhile, they'll continue to nail down the actual pantheos of fundamental particles, the exact strength of fundamental forces, the exact nature of reality.

What is it all about?

What is it that drives the universe? What is the right way to look at it?

This is not an answerable question. All we can see are a set of rules, rules that seem to apply everywhere. To be honest, what does it matter how the universe sees itself? We only care about how it is manifested, and our understanding of that.