“Physicists often will want to go into biology and want to predict everything from first principles. And you can't do that. Every system has its own scale of complexity. Just because you can solve the Schrodinger equation for a simple system doesn't mean you can then start applying it to understand memory, like the brain, even though they're all governed by the laws of quantum mechanics ultimately.”
The Peterman Post · Software Engineering & Infra · November 2026
Context
Asked for the main differences between physics and biology, Ramakrishnan, who trained as a physicist himself, says biology is settled by experiment and needs control experiments. This is his criticism of physicists who move into biology and keep thinking like physicists.
Transcript
…Are your colleagues going to be good? Are they going to be stimulating? Do they have the infrastructure that you need to get top-level science done? So those are the things you should look out for. And there are lots of places like that. And they'll vary depending on what area you're interested in.
I thought it might be interesting since you deeply studied physics and biology to ask you what do you think the main differences are between the subjects, aside from the obvious subject matter.
Well, biology is very complex. So you have a lot of questions in biology are settled by experiment. It's very hard to predict theoretically what will happen. Although, as we discussed, you know, with AI and computational methods, people are trying to do more prediction computationally. But it is a highly complex system. And in the end, you need experiments to settle what's going on. And I would say, because it's so complex, if you want to study the effect of something, how do you know that whatever changes you see are because of whatever you did or it's not just some random thing? So in biology, you always have to do control experiments. You add your factor, see what happens, and then you see what happens if you don't add the factor. So you have to carefully design control experiments. And of course, in medicine, this is why you have randomized clinical trials which have proper controls. That's an even more complex system, like a human being, because we're all highly variable and so on. But in physics, you can construct an experiment that's extremely simple, where the answer, you can, from the result, you know exactly what's happening. So physicists often don't think about control…
In a QA somewhere, someone asked you why you got interested in physics. And you replied that when you were young, physics and math were logical and pure in a sense, and biology was more memorization.
Oh, yeah, the way it was taught, especially in India where I grew up, was it was all rote memorization. And I never got a sense of biology as a kind of interesting detective puzzle. And I didn't get that until much later.
Yeah, why is that? When I went to high school as well, it was a similar, there was maybe a tier list of math and physics are kind of the pure ones at the top, and then maybe chemistry and then biology is even more memorization. Is that in the nature of the subject or in the nature of how it's…
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