Is there a Doctor in the house? A Professor?
My brother ran into someone calling herself "Doctor X" and "Professor X" recently, who turns out neither to be a Ph.D. or M.D. nor apparently to have a Faculty position at the institution she is teaching in. While in my opinion highly unethical, this situation is not uncommon. It seems to be partly a result of confusion about what the titles "Doctor" and "Professor" mean. Let me try to clear up some of his confusion, and perhaps yours…
Doctor
First, let us take on "Doctor". Specifically, there are some folks who are unarguably, legitimately entitled to the title Doctor. Anyone with an M.D. is a Doctor. Anyone with a Ph.D. is a Doctor. In modern usage, anyone with a Doctor of Medical Dentistry degree is a Doctor, as is anyone with a Doctor of Divinity degree. There are a number of obscure academic Doctorates out there also recognized as "Doctor" in polite modern usage. There are interesting border cases. For example, a Psychiatrist, who has an M.D., is entitled to Doctor, as is the typical Psychologist, who has a Ph.D. It is not unheard of for a medical research to have both an M.D. and a Ph.D., making them doubly-entitled (and perhaps entitled to "Doctor Doctor").
In many U.S. clinics these days, it is common to find Physician's Assistants referred to as "Doctor". While this fits the popular notion of "Doctor" as caregiver, in my opinion it is a dangerous practice. A Physician's Assistant has extensive training, but much less than a Medical Doctor, and the supervised learning component of a P.A. degree is much smaller than for an M.D. As such, there are certain types of advice that I feel a P.A. is unqualified to give, and certain issues I would want the advice and opinion of an M.D. on. These days, I usually politely ask an unknown "Doctor" whether they are an M.D. so that I know what qualification I am dealing with.
It is not uncommon for folks to abuse their Ph.D. by deceptively calling themselves "Doctor" while working in medical and related fields, even if their Doctorate is in an unrelated area. For example, radio personality "Doctor" Laura Schlessinger's Doctorate is a Ph.D. in Physiology—not an obvious qualification for dispensing mental health and relationship advice.
Finally, some folks simply call themselves "Doctor" because they give out therapy. Note that I know of no state that makes this practice illegal (although I am not a lawyer). As far as I know, anyone can use the title Doctor, as long as they don't specifically represent that they hold a specific degree or qualification. Caveat Emptor.
Professor
The title "Professor" is even more complicated. In accepted usage, the title is restricted to someone who is "on the Faculty" of a College or University. This can be a bit imprecise, however; one can "have Faculty rank" at many Universities, including mine, while being a staff person rather than a Professor. Further, the exact definition of Faculty varies from institution to institution, and even by usage within an institution. Portland State University has a number of "instructors", who are hired on a term-contract basis only or primarily for teaching and curriculum development. While these valuable folks are probably not formally "Professors", students are certainly not discouraged from referring to them and treating them as such.
The bare title "Professor" is rarely used by real professors, formally or informally. Formally, the title is usually qualified in some way that more precisely describes the position. For example,
my current title of "Assistant Professor" has a specific meaning at Portland State, one shared by most colleges or universities. This title means that I am tenure-track (working toward achieving tenure), but not yet tenured. (Tenure is a whole story in itself; I will try to remember to address it in a later posting.) If I am granted tenure this year, my title this Summer will be "Associate Professor"—a further promotion to "Full Professor" will eventually be possible. In general, folks who are "Full Professor" just sign "Professor", but by the time they reach that title there should be little ambiguity. Many Full Professors are holders of an "endowed chair", so they use their chair's title: "Tektronix Professor of Computer Science" or "Fariborz Maseeh Professor of Computer Science" at our institution. There's also "Professor Emeritus" (was some kind of Professor at PSU until they retired, may still teach), "Research Associate Professor" (not tenured or tenure track, funded entirely by "soft" money such as grants), "Adjunct Professor" (not tenured/tenure track, doesn't work at PSU but does teach here occasionally).
The qualifications for a given kind of Professsor title vary from institution to institution, although most are similar to PSU. At West Virginia, for example, my friend just signed on as a pre-tenure Associate Professor. Likely his title will remain the same once he is tenured.
In particular, most US institutions have no hard-and-fast rule that any kind of Professor is required to have a Ph.D. (in any area, much less their subject area). However, at the better grade of institutions the only exceptions are typically granted to (a) folks who got into the field so long ago there was no Doctorate in it yet, (b) folks who are such recognized and influential experts in their area that their lack of Doctorate is regarded as a ludicrous accident, and © Adjunct or Research Associate Professors with some kind of graduate degree who are experts in some particular narrow area.
Legally (again, as far as I know, not being a lawyer and all) the term "Professor" is even less well-controlled than "Doctor". If one claims to be a Professor at a particular institution, that institution can certainly repudiate the claim with legal force. But if my 7-year-old calls himself "Professor Benjamin" online, as far as I know there's nothing anyone can do about it.
Comments
In summary, the bare titles "Doctor" and "Professor" conceal a complex web of possible qualifications. It is certainly possible to be a Professor without being a Doctor, a Doctor without being an M.D., and a teacher or healer without being any of the above. Hopefully folks who are aware of the possible confusions will be better equipped to deal with issues around these terms.