...is not our growing tendency to appoint no instructors who are not also doctors [i.e. holders of a Ph.D.] an instance of pure sham? Will any one pretend for a moment that the doctor's degree is a guarantee that its possessor will be successful as a teacher? Notoriously his moral, social, and personal characteristics may utterly disqualify him for success in the class-room; and of these characteristics his doctor's examination is unable to take any account whatever. Certain bare human beings will always be better candidates for a given place than all the doctor-applicants on hand; and to exclude the former by a rigid rule, and in the end to have to sift the latter by private inquiry into their personal peculiarities among those who know them, just as if they were not doctors at all, is to stultify one's own procedure..... The truth is that the Doctor-Monopoly in teaching, which is becoming so rooted an American custom, can show no serious grounds whatsoever for itself in reason. As it actually prevails and grows in vogue among us, it is due to childish motives exclusively. In reality it is but a sham, a bauble, a dodge, whereby to decorate the catalogues of schools and colleges....not really against the Ph.D. entirely, but against their monopoly in teaching and the general importance placed on them.
-- William James, "The Ph.D. Octopus" (1903)