I chose my own research questions for my PhD. So did many people I know. And, when supervising my own PhD students, I preferred them to work on their own problems, all other things being equal [1].

The reason is that choosing what problems to work on is a fundamental research skill. Someone who doesn't learn that skill hasn't really learnt to do research.

This isn't to say that a student shouldn't spend time talking with their advisor about choice of problem. Of course they should -- they should talk to as many people as possible! But the responsibility for the choice of problem should be theirs. If that's not the case, then they're missing much of what it is to do research.

To quote a letter of Feynman to a former student of his ( http://genius.cat-v.org/richard-feynman/writtings/letters/pr... )

"I had another Ph.D. Student (Albert Hibbs) [who worked on] how it is that the winds build up waves blowing over water in the sea. I accepted him as a student because he came to me with the problem he wanted to solve. With you I made a mistake, I gave you the problem instead of letting you find your own; and left you with a wrong idea of what is interesting or pleasant or important to work on..."

[1] This is actually pretty complicated. Many students don't have ideas they're confident pursuing. Some don't grow into it, even after gaining some experience solving research problems. That presents challenges. And sometimes students badly misjudge what is important or interesting to work on. Should a supervisor interfere when that's happening? It depends. Making mistakes in choosing which problem to work on is an important part of learning to do research. So some floundering around is fine. But allowing it to go on for years and years is just cruel.

You're probably among the top 5% (if not top 1%) of people in physics, and you attended top institutions. That's fantastic (I really mean that), but it gives you a skewed view of academia.

Most physics PhD candidates do not have free choice of research questions (or, at best, they are spending their "10% time" on their own questions, which is what I did).

Thanks for the kind words.

On institutions: I did my PhD at the University of New Mexico. A fine institution, but also not Harvard / MIT / etc. I went there because Carl Caves had created a great environment to work on quantum information. Carl encouraged me to work on whatever problems I wanted, but was also happy to provide advice upon request. My fellow PhD students enjoyed similar freedom, and I believe it benefited them enormously as well.

Edit: To clarify my earlier comment: I am certainly _not_ saying that it is universally the case that people are able to choose their PhD project. That's not true, especially in fields involving expensive experimental equipment. I'm saying that someone not able to choose their project is being badly trained. It should count as a very heavy mark against doing a PhD when the advisor believes they should control the direction of the project.

I bet you work in an inexpensive paper/theory field (math, theoretical physics, CS), and your parent poster works in an expensive wet lab field (bio, chem, eng).

The cost/benefit tradeoffs are atrkly different.

You're right about my background. Still, I know many experimental PhD students who enjoyed great freedom in deciding what to work on. It's not always possible in the most expensive experiments -- a student probably can't easily repurpose the LHC for their own ends. But outside those huge experiments there's often a lot of flexibility, provided (a big caveat!) the PI is on board, and the student has ideas of their own.

In my PhD field (physics), there was a middle ground for most students.

Proposing a research project is a lot like pitching a product idea. If you bring your own money, or don't need any, then you can do whatever you want, including failing. If you need funding, space, collaboration, mentoring, whatever, then your pitch has to mesh with the interests with other people.

But even if given a project, it's not really a "project" in the sense of having a plan, budget, and timeline. Depending on the professor, the project may just be a vague concept, with no idea of how to carry it out. That was the case with my thesis project. I started with an inchoate idea, and ended up developing an experimental technique that opened up a new research program for my advisor.

There are professors who assign cookie cutter projects, and I think it's a disservice to their students.

It isn't in a vacuum, people working on a PhD are free to pursue any topic that they can fund and get a supervisor to agree with.

Yes - the subjects of advanced study should be selected by the government. Individual researchers should operate like an army, going where they are told.

/s

Why not? You at of course free to fund your own research with whatever patronage you can arrange. You'll need to convince convince people you are worth it though, and an apprenriceship is one well understood way.

Who would have enough money to sponsor research?

Bored patent clerks?