What concerns/worries a potential PhD supervisor might have when he/she sees an application from someone who already has a PhD and applying for the second one? The fields of study are distantly related (engineering - physics).

What questions should be addressed in the initial letter by the applicant?

The first PhD is not a complete failure but an applicant wants to pursue his ultimate interests. The applicant has a postdoc position secured but has serious doubts working in the field that is not of major interest for him. Postdoc applications in the field of main interest didn't result in getting a position.

  • 1
    Having no PhD is a major barrier to success in academia. Having a PhD in a different, but related field is much less of a barrier. I'd question whether the applicant needs to get the second PhD to pursue these interests.
    – user24098
    Commented May 13, 2016 at 16:05
  • 3
    You should perhaps read this.
    – user9646
    Commented May 14, 2016 at 7:05
  • Najib Idrissi, thank you for the link! It's kind of pointless to begin a polemic with an old post from the different thread, still... Collecting degrees is not a goal for me - I will be happy with one, if I can do what makes me happy without having a PhD - I won't do PhD at all. If it helps not to tell that I already have a degree and it is legal - I will not tell.
    – InCheck
    Commented May 14, 2016 at 21:55
  • It is that from my limited experience applying for postdocs and personal bias, the first degree doesn't open the doors I want to open. As mentioned in the link, it is rather sad situation but I'm afraid it could be even sadder to tie yourself to something that is not for you. The story about Raoul Bott is an outlier, stories about people stuck with something they don't like are not.
    – InCheck
    Commented May 14, 2016 at 22:12

4 Answers 4


Here are the concerns I would have:

  • Is this person seriously going to spend another N-years getting a second doctoral degree, and then go seek a postdoctoral position before pursuing the job they presumably want to have? If so, what is this going to do to their career, and do I want to be party to that?
  • How did this person get all the way through a PhD in something other than their "ultimate interest"? Do they know what their "ultimate interest" is now?
  • Did they try to switch fields mid-PhD, or get some credentializing in the field they wanted to be in. If so, how much? If not, why not?
  • Do I think this person has strong prospects in this field? They've failed to get a postdoc - was this the result of just a small number of applications, or genuinely a problem. Again, if their postdoc application was weak, do I think it could be salvaged?
  • Thank you for your reply! It is very useful to get perspective from the "other side". It is not easy to address the second comment. I don't have a rational answer to this question. Basically, I feel bad quitting something half way. And you never know, should one give up when it is difficult or it is just something that everyone else has to deal with and you just will be a quitter. I decided to persevere. There is no program related to the filed of interest where I'm right now. I took courses that remotely related - got to use what is available. I also steered current project towards interest
    – InCheck
    Commented May 12, 2016 at 21:43
  • Regarding the last note. I got a postdoc in the field other than the field of interest. Some of the postdoc applications in the field of interest were turned down because "applicant has no experience in the field of proposed research". Is it useful to include a short document with research ideas that are extension to the work done by the potential adviser when contacting him/her?
    – InCheck
    Commented May 12, 2016 at 21:58
  • 2
    @InCheck If you're not coming into a postdoc from the field, your cover letter etc. should absolutely try to communicate "I have interesting and potentially useful thoughts in this area".
    – Fomite
    Commented May 13, 2016 at 3:58

I think every PhD graduate was in your situation to some degree. Let me advise you to do not waste (you read it right!) your time for the second PhD degree. Nothing will come out of it. You could get a posdoc in the area that you like if it is applicable. Also you could find a job in the area of your interest. Again, don't waste your time, you already learned your lessons during your PhD degree and it is time to move on.


To bring in the key idea from the linked question:

I would expect one thought might be 'What does this person think a PhD is about?'

A PhD is not just about learning some new facts. That can be done by getting a book out of the library. A PhD is also about learning to be a researcher. Some of that will be the same for any subject - getting better at thinking carefully and reasoning well. Some of that will be shared between, say, sciences - getting better at research techniques, learning to write papers, style of teaching and presenting. The smaller part that is subject specific is often learned by doing a postdoc, or just as part of life as an academic.

Given that, I would think there needs to be a reason why a second PhD is the best way of acquiring new skills, rather than the alternatives.


I know of one person who has two PhDs in somewhat related fields. His first PhD was on pure mathematics, and he managed to complete his second PhD in 3 years in operations research. For this person, earning this second PhD allowed him to get a job in a business school which pays quite a bit more than a job at a math department. He was also able to complete his PhD faster than average (the average/median at his school was about 5 years).

I know another person who got a PhD in physics and is now studying for a PhD in finance. While the fields are related, I suspect he is doing so because a PhD in finance would open doors that would not open with a PhD in physics.

To summarize, it is not typical for a person to study a second PhD but some people choose to do so and it can work out for them.

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