Why is Doctor Who always called the doctor?

Answer 1

"The Doctor" is a name the character uses throughout the series since its beginning in 1963. However, in the opening series Named the "An Unearthly Child" he was referred to also as "Grandfather" by his granddaughter Susan. The character's true identity has never been revealed, though there have been hints as to his backstory all the way through, most prominently in the Seventh Doctor's era, 1987 - 1989.

During a conversation between the Doctor and the Master in the 2007 episode The Sound Of Drums, both characters state that the other "chose" their names (ie Doctor and Master. "Doctor" being "one who makes people better", while "Master" would be "one who subjugates"). While this has been alluded to many times in the series history, I believe this is the first time it is stated categorically, for the Doctor at least. Neither character's name has been revealed in the series thus far. In the 1988 serial The Happiness Patrol, the Doctor tells one character he was given the nick-name Theta Sigma at the Academy. I have seen several answer sites such as this where people have stated that Theta Sigma is the Doctor's real name. This is not correct.

In the previous serial, 1988's Rememberance of the Daleks, the Doctor leaves a calling card, which features a prominent design resembling a cross between a capital letter D and a Question mark. The card also features other text, consisting of various Greek, Cryllic and other nonsense symbols.

In the novelisation of Spearhead From Space (Doctor Who and the Auton Invasion) when the Brigadier asks the Doctors name, the Doctor wrestles with himself whether to tell the Brigadier or not, thinking 'He'd never be able to pronounce it anyway' an plumps for the oft before and oft since used alias 'Doctor John Smith".

During the 2011 episode Let's Kill Hitler, during a discussion on the nature of "The Silence" previously thought to be a species), it is revealed that they are actualy a religious order who believe that "Silence will fall when the question is asked..." "...The first question. the oldest question in the universe. Hidden in plain sight". What the question actually is, was at the time, unknown.

In the finale of the same series, The Wedding Of River Song, Dorium expands on this, stating firstly that "Silence mustfall" is a 'better translation. He refers to a specific prophecy, "On the fields of Trenzalore, at the fall of the eleventh, when no living creature can speak falsely or fail to answer, a question will be asked, a question that must never, ever be answered". At the end of the episode, Dorium goes on to say that the Doctor had already worked out what the question is, and that he'd been running away from it all his life. "Doctor Who?" This is clearly building up to the series 50th anniversary in 2013.