Does the theme and field of activity in the process of working on PhD give freedom or impose more restrictions?

Question

I was thinking about what kind of future a person can build who has gone through the defense of a dissertation and received a PhD.

On this part of the path, the young scientist managed to work in some narrowly focused industry, deeply studied a special problem, delved into the peculiarities of the scientific community in the specialty in which they are defending their dissertation.

And I had a question: is the PhD degree, which is associated with a narrow topic, with a narrow field of activity, with a narrow specialization, a "stigma for your entire professional life" or, most importantly, "you received a PhD and, hopefully, managed to see the bridges between your work and other areas where your knowledge and results can be useful?"

Suppose a person has a master's degree in robotics, actively uses this knowledge in writing a dissertation, but the final result solves a narrow problem in the field of energy. Accordingly, the applicant defends their dissertation in the community of power engineers, and not robotics.

It turns out that a person is now always connected with energy (for example, with solar power plants) and will not be able to work in the field of robotics? Or, after the defense, can they switch their interests from solar power plants to robotic spacecraft systems?

I really lack clarity on this issue, because it is sometimes very difficult to predict events over an interval of 2-3 years, as well as a change in scientific interests, and I am afraid that PhD can put an end to the choice of a further professional path.

Answer 1

No, there is nothing necessarily limiting to doing a dissertation in a narrow topic. That is, no external limits, though a person has, for the moment, taught themself to focus on a small part of a broad canvas.

It is common, nearly universal, for people to migrate their interests over their career. Even a new faculty member facing a tenure review in a few years can move to another area, though it is easiest to move to a related one, or possibly one where the current faculty has a lot of interest and expertise.

I personally wandered through a lot of the computing landscape from language implementation to databases to human factors, etc.

Moreover, in some fields you are almost forced to move as the landscape changes. Some specialties become very mature and the opportunities for innovative research become fewer. Fewer people work in some specialties in favor of others with better opportunities.

A doctorate teaches you to do research and to think in a certain way about extending knowledge. It isn't limiting unless you make it so. It gives you skills to explore new worlds, not boundaries to force you into old ones.