This is a broad and complicated question in search of a general answer.
Within the many medical research specialties, how would the knowledge base of a newly minted post-doctoral fellow at a top-tier U.S. university compare to that of the tenured faculty? On one level, it’s obvious that a medical researcher with 30 years under her belt will have amassed lots of knowledge, but is the disparity between her and a post-doc that huge? Could the post-doc keep up in a very technical conversation between two faculty members on a given medical research topic, or would he clearly be out of his depth? My impression is that faculty members are going to have a significantly deeper and broader knowledge base, but if that’s the case, then wouldn’t the lion’s share of the major breakthroughs be scored by researchers in their 50s and 60s? (We know that, within the world of physics, for example, many of the paradigm-shifting advances come from the 20something physicist.)
I’m not sure there is a simple answer to that. My experience is in industry, long time researcher (me) versus new PhDs (the people I hired.) The new people had a much better understanding of new discoveries, but I had a better understanding of how things fit together, which came from living through a lot of the development they learned about in school.
It also depends on whether the professor has been working deeply on one or two areas, or if they are more of a generalist.
This is conflating several things. Firstly, yes, technical knowledge and expertise accrues fairly steadily over time - whether its medical specialisations, other disciplines, sport or whatever. The caveat is that you have exposure to depth and breadth of experience to really make it work. But comparing your recent post-doc and an old professor you’ll know who knows more [content] and knows what matters [context or significance].
The second is capacity to innovate - this is partly brainwork but also social things, like immersion in the latest trends and riding the wave of the newest ideas, and also the way post-docs are positioned to need to make a big splash fast or be condemned to obscurity. In my field (not medicine) there is a lot of big talk in research proposals about how dramatic discoveries will be and how they will change the way we think etc. Older and tenured professionals don’t need to talk that kind of self-justificatory bollocks quite so much.
The third thing is that in the university system while the tenured may dream of running a lab on research grants, they will be crushed under teaching (which certainly broadens and updates their knowledge), admin and countless pointless time-wasting and brain-zapping tasks. You need clear air to think deeply and produce, and its very hard to find any. That’s where the youngsters are not nearly so burdened because they will be employed for one task on contract, whether its teaching or as part of a research team.
There’s also a separate discussion to be had about the disappearance of tenure in universities and creation of an academic gig economy, which will only drive the rush for limited funding with over-hyping of the importance of the research value, and the ageing of the academic cohort who will spend even more time on admin.
My thought is that once a person graduates with an advanced degree, yes, they know a lot… but after working for a while, they probably have a field they specialize in - far more specialized than just a degree. The guy researching crystallography for metallurgical science, or doing low temperature research, and the guy doing fusion research probably don’t have a huge amount of overlapping experience, although they do have some far more advanced common knowledge than the average MSc. OTOH, a particle physics researcher and a fusion researcher probably have a lot of common ground. This issue would likely also appy to whatever topic the graduate’s PhD would be in…
So it depends what the topic of conversation is too…
A quick drive-by note (from a physics viewpoint but generally applicable to at least other STEM fields)…
Comparing “random postdoc” with “random tenured faculty” is sort of apples and oranges due to the huge selection pressures on the latter group. Given some reasonable levels of base talent, hard work, and career interest, the undergrad → grad (PhD) → postdoc sequence doesn’t thin the numbers by huge margins. The postdoc → untenured faculty → tenured faculty sequence, in contrast, represents a huge reduction in numbers, so it isn’t just a matter of comparing people with less experience to people with more experience. It’s comparing people with less experience to people with more experience who have been specifically selected as excelling in various hard and soft skills and who have continued to demonstrate effectiveness as evidenced by their promotion to tenure.
So, answers to the more specific hypothetical questions depend heavily on how the comparison pools are constructed.
In a freshman English class, a professor told us that he had 500 times the knowledge of the subject that we had.
I doubt if a new Ph. D. could have more than 100 times us. There simply wouldn’t have been enough days in a life to manage that.
In the real world, even in the sciences, most breakthroughs come from a group working under the supervision and active participation of a senior scientist who is much older than the grad students and post docs. Only a tiny few advances come from young individuals, and then only in a few narrow fields. But they get all the publicity.
I have many postdocs in my lab, and have mentored over 50 in my career. For specifics, the postdocs generally have a MUCH better grasp than I do; that’s why I hired them in the first place. I almost always have a better grasp of the big picture and history of the field then they do - that’s my 25+ years of experience talking.
Brings to mind Dr. Banting, a recently graduated young doctor who came up with the theory as to how to get insulin and use it to treat Type I Diabetes. He and his assistant, a medical student (Charles Best) were given an area in the lab to work in by the lab manager, McLeod. After several months of trials, the pair came up with a way to isolate insulin which could be injected and give diabetics a normal life.
So when it was time to award a Nobel prize for this significant breakthrough, the prize went to… Dr. Banting and Dr. McLeod, because “graduate students don’t get Nobel prizes.” IIRC, Banting was very upset about this and gave half his share of the prize to Best.