I recently decided to watch Doctor Who, and started viewing the 2005 version. I have the first two episodes from the first season, and I can't help but wonder what is the etymology of the name "Doctor Who"? And why does the protagonist call himself "the Doctor" (or is it "the doctor")?
In the very first episode of Doctor Who (way back in 1963), the Doctor has a granddaughter going by the name "Susan Foreman", and the junkyard where the TARDIS is has the sign "I.M. Foreman". Barbara, who becomes one of the Doctor's companions, calls him "Doctor Foreman" (probably assuming that is his name given his relationship to Susan), and Ian (another early companion) does the same in the second episode, to which the Doctor says:
Eh? Doctor who? What's he talking about?
"Foreman" is most likely selected as a convenient surname for Susan to use because it happened to be on display near where the TARDIS landed.
Ever since then, there have been a series of "Doctor who?" (as in, "what is his name?") questions by various companions and people that he meets. This is sometimes a serious question, and sometimes a joke, often one made by the Doctor himself. However, he never actually goes by the name "Doctor Who" - it's the title of the series, not the character.
Except that, for the 1st through 4th Doctors, the title credits used the name "Doctor Who" or "Dr Who", even though he was not called this on screen. From the 5th through 8th Doctors, the credit was "The Doctor", then for the 9th Doctor it went back to "Doctor Who". With the 10th and 11th, the credit has gone back to "The Doctor" again.
With the 10th and 11th Doctors, hints have been made about the significance of the Doctor's name:
- Madame de Pompadour says "Doctor who? It's more than just a secret, isn't it?"
- The Carrionite Lilith says "Why would a man hide his title in such despair?"
- Much significance is made of River Song knowing the Doctor's name, with the suggestion that this is part of marriage / a wedding.
It's likely that more will be revealed about this, although it seems unlikely that his name will actually be revealed.
The Doctor has never revealed the origin of the alias "The Doctor", although it's implied that this is a reference to the doctorate ("PhD") type of doctor rather than a medical doctor (i.e. he is a scientist). Explanations as to whether or not he studied to gain this title, and what he studied, and with whom, are varied and inconsistent throughout the history of the show.
The Doctor often uses the name "John Smith" (or even "Doctor John Smith") - this was first used by the 2nd Doctor's companion Jamie McCrimmon, but has been used regularly since then. At the Academy on Gallifrey, he apparently went by "Thete" or "Theta Sigma" (originally revealed in The Armageddon Factor, and confirmed as a nickname in The Happiness Patrol).
Other Time Lords have mocked him for using the title "Doctor". When talking to the Master at the end of The Sound of Drums (a 10th Doctor episode), it is revealed that the Doctor and Master both chose their names: the Master describe's the Doctor's choice:
The man who makes people better. How sanctimonious is that?
However, in The Lodger, the 11th Doctor says:
I'm the Doctor. Well, they call me 'the Doctor', I don't know why; I call me 'the Doctor' too, still don't know why.
The series is called "Doctor Who". This was entirely for marketing reasons. The character refers to himself as "The Doctor". Other characters referring to him as "Doctor Who" is a long-running in-joke.
Originally it was an effort to depict the character as a nameless mysterious but academically learned scientist. The 1st Doctor was often depicted as engaging in original scientific field research as a kind of hobby.
In the modern series it is more a conceptual label for his (preferred) philosophical approach to the universe and it's inhabitants. He likes to think of himself as the man who would first do no harm and try to heal conflicts he encounters.
At a later point he half-jokingly refers to himself as the "maintenance man of the universe".
Though I doubt a series called "Janitor Who" would have been as popular.
It's been theorized that Time Lords take on titles or roles, in place of names, at some point in their lives or careers. Notable entries include The Doctor, The Master, The Rani, The Warlord, The Meddling Monk, and potentially one or two others I can't remember from the classic series. From the new series, "Corsair" could be a name as well as a title.
Interesting to note is that the word 'doctor' is known throughout the universe (according to River Song) as 'a wise man who helps people'. She suggests that the Doctor is the very reason for that, he calls himself the doctor and aids people, thus making everybody familiar with the word doctor.
Yet at the same time, it is very likely that the doctor took the name because he wants to help people. In other words, he picked a word that he himself gave meaning. Even his very name is a timeloop paradox.
In William Hartnell's story 27 "The War Machines", the computer WOTAN (Will Operating Thought ANalogue) spoke of The Doctor as "Doctor Who", but the novelisation also written by Ian Stuart Black published by Target Books in 1989 (ISBN 0-426-20332-1) substituted "the Doctor" for these instances. So there you have a retcon intent by the original author of the story.
According to commentary tracks on some of the DVDs, it was to be left as an open question in the series, but not all writers got so instructed. I think it was discussed on the DVD for "Doctor Who and The Silurians" while pointing out that it was not intended to be titled that way. It was SOP to exclude "Doctor Who and" included in the titles, but it made it through that time and they stuck with the mistake for all parts of the story rather than have them not match.
Often the Doctor is "The Doctor" with the capital T, such as in the year 5000 on a medical record.