[hgoel]

Is there a reason you went for 3 PhDs? Especially since they're all in STEM? To me it's a red flag because the point of a PhD is to learn to do research, you don't need to get another one to move between fields (especially within STEM), just need to do research with people in those fields and gain experience.

[iliatoli]

Each PhD was in a different country and decade. Mathematics (Pisa, 2000s), Quantum Chemistry (UCF, 2010s), Materials Science (UTD, now). The fluorographane work exists because all three converge — the barrier calculation is quantum chemistry, the proof structure is mathematics, and the material is materials science. I didn't plan it this way.

[hgoel]

Ah, that's interesting. Different countries can be a fair reason I suppose.

[iliatoli]

Fair question. In my case, each PhD opened a door that didn't exist from the previous position. The mathematics PhD in Italy didn't give me access to computational chemistry labs in the US. The quantum chemistry PhD didn't give me access to materials science groups. Immigration, funding structures, and departmental boundaries created the path — not a desire for credentials. The fluorographane paper is the proof that the path was worth it.

[juleiie]

Some people actually enjoy studying and learning in these spaces. Does everything have to be optimized for?

[hgoel]

What's so special about specifically the PhD student experience that isn't accessible once you have the PhD?

My experience has been that research became much more fulfilling after finishing my PhD. I got more research independence, the level of work I was expected to do increased, and as a bonus, my salary almost tripled. It was like having the world open up, and starting to really experience being a scientist without my PI protecting me.

I was curious about their decisions because if you're taking on the opportunity cost of a PhD, it's probably because you enjoy research, but if you enjoy research, you wouldn't keep going back to the starting point. So, without additional context, it seemed like they just wanted the credentials.

I think it was also worth asking because universities often want to know why you want another PhD, since from their perspective, spending that funding on someone with no PhD potentially creates a new researcher (vs spending it on an existing researcher). So, if they managed to get into a PhD program again, they probably had a good reason.

Their response about different countries is an explanation (especially from an immigration angle), it's not like I'm asking them to lay out all their personal circumstances behind the decision in detail.

[nine_k]

3 PhDs is quite some dedication to science, given that a PhD student life is neither that of plenty nor leisure.

[juleiie]

Some people do not need to worry about material possessions as much as some others because of the random birth wealth lottery. Then they can pursue interests in less goal driven ways than it would otherwise seem wise

[chmod775]

In many European counties it's easily feasible to just study all your life while working ~20 hours / week. I won no lottery but had no issue spending a decade of my life pursuing interests at universities while working 20-30 / hours a week in a comfortable software dev job.

If I'm paying for "free" education with my tax euros, I might as well use it.

[alemwjsl]

There are lots of stipends etc. If you don't plan to have kids, and you don't care about luxuries, you will have healthy food and a roof and not be thinking about money. Probably the decision is to forgo luxuries and child raising, and hope you don't need to help a sick relative etc. if you want do to this forever. But it is not impossible in STEM.

[cluckindan]

That works as long as you don’t expect to graduate: in many EU nations, higher education students are required to complete at least 60 ECTS credits per year, or lose their study right / enrollment.