Although I enjoyed the recent Tofugu article/podcast on Japanese Name Enders, I was disappointed to find that it did not cover a name-ender topic which I had been recently wondering about. As such, I was someone in the WaniKani community might be able to answer my (apparently non-podcast-worthy) question:
Is 先生 acceptable to use as a name-ender in modern Japanese for people such as PHDs (who are not necessarily teachers/professors) or for professionals such as lawyers?
My (admittedly beginner’s) understanding is that 先生 is a title that is conventionally conveyed to people that are “wiser” than you. This includes teachers, physicians, lawyers, politicians (yeahyeah an extra layer of quotation marks here, I know), etc.
It’s sometimes also used for high-level managers AFAIK.
I don’t know about PhD’s in general.
My impression is that someone has to be a lot wiser than you to be called 先生 without seeming over the top when they don’t have a real teaching function. Old, influential and/or famous seem to be the key here.
The neutral term for Ph.D. is I think 博士 (はかせ), but I don’t know if it is ordinarily used as a さん replacement or something.
I think 先生 basically refers to anyone with a high level degree or anyone far enough above you that they are not 先輩.
(Medical) Doctors are usually called 先生 but I think generally for a professor or someone in a STEM field who is not directly related to you then 博士 is more accurate.
I think to summerise, 先生 is a term of respect, so shouldn’t necessarily be used in ordinary situations like you wouldn’t throw around さま.
博士 is very formal, and won’t be used in normal conversation. You would indeed use さん usually. And again, it’s only in the case that the person isn’t actually a professor (so a postdoc, or someone who left academia).
I came across this yahoo answers page and from what it seems, 先生 is a pretty flexible term when dealing with someone who has attained a special skills but is not quite at the level where the speaker feels comfortable using さん. Quite a few of the respondents mentioned that using such a title expresses respect toward the target it’s given. I can’t speak about the reliability of the answers, but it seems to be something even Japanese people seem to be unclear about.
It certainly seems like, unless the person is in a teaching position, it is probably best to follow @kylesama’s advice that you shouldn’t throw around enders like 先生 and さま. (Good advice, but somewhat ironic considering his screen name!)