What makes that even more absurd in my books (apart from fostering an unhealthy academic culture) is that the purpose of a doctoral dissertation is essentially to show that you can do proper original research.
Getting a null result doesn't invalidate that in any way.
Exactly. In our area, the dissertation itself and defense were evaluated on the presentation of the research, not on the results, provided that they followed the proposed plan.
If you have a committee of experts who carefully evaluate a proposal and decide it's good, the results are as they are.
Broadening the discussion a bit, it seems one feature of science, as opposed to, say philosophy, is that the conclusions regarding a hypothesis are not knowable a priori. I think in contemporary academics there's some implicit idea that the quality of a researcher lies in their ability to identify hypotheses that are "correct", as opposed to simply following through with good but ultimately "incorrect" hypotheses. There's a bit of a roll of the dice involved with science; if there isn't, it's not science.
> it seems one feature of science, as opposed to, say philosophy, is that the conclusions regarding a hypothesis are not knowable a priori.
That should be a defining characteristic of any academic inquiry, regardless of whether it's science or not.
I have no training in non-quantitative fields, and my academic experience is from CS where the "science" part is often so-so. As such this should be taken partially as a layman view. However, my impression is that while in non-scientific academic fields the research isn't necessarily taking the form of explicit hypothesis testing, more or less similar criteria for intellectual inquiry should apply.
The research might be more about observation and critical (often non-quantitative and non-absolute) evaluation of arguments, and as such the validity of the methods (such as whether the hypothesis is assumed or genuinely questioned) might not always be as easy to judge [1].
The process might not be as easily formalized or judged as in science, but the mentality of critical inquiry should be similar. If the hypothesis is assumed and not questioned, that's no longer any kind of academic inquiry. It becomes politics, in the pejorative sense.
> I think in contemporary academics there's some implicit idea that the quality of a researcher lies in their ability to identify hypotheses that are "correct", as opposed to simply following through with good but ultimately "incorrect" hypotheses.
I think that's partially just psychology and human nature. We like results that make us directly know (or think we know) more, and results that basically tell us we still don't know less. Few people like uncertainty.
The society outside of the academia certainly values the former more than the latter, and funding and other external incentives probably exacerbate the underappreciation of negative results.
[1] Or perhaps it is, to an expert, but having that judgment would require the kind of experience in those fields that I don't have.
Getting a null result doesn't invalidate that in any way.