A few comments. 1. The word 'doctor' is not a title of nobility. Endless arguments about which doctorates are "higher" than other doctorates reminds me of the pretensions of faded European aristocracy. (And I respond with the faint contempt that many Americans reserve for such things.) There's entirely too much ego involved with this whole doctoral subject. 2. It's up to ME who I address as "doctor". Addressing people that way is an expression of respect and I get to choose who I respect. 3. In most jurisdictions, use of the word 'doctor' is not regulated by law. So technically, anyone can use 'Dr' with his or her name, regardless of the degrees that they may or may not have earned. 4. I'm inclined to think that any degree awarded by a credible institution with the word 'doctor' in its title is a real doctorate, provided that it is the degree that typically qualifies somebody to teach the subject at the university level and is the degree normally possessed by professionals at the top of their game. 5. I don't consider the modern PhD to be the paradigm for all doctorates. Doctoral degrees have been around since the 13'th century, at least. Modern PhDs didn't appear until the 19'th century, 600 years later. If any doctorate deserves to be the historical paradigm for all of them, it's the professional doctorate. 6. When I'm determining which doctorates I respect more than others, there's lots of variables that go into that decision -- The general reputation of the school that awarded the degree, the broad subject and specialty emphasis of the degree, the awarding department's reputation in that area, the individuals that the graduate actually worked with, and more. It's very much a matter of personal taste.