Culture-relativity

And most modern medical doctors aren't actually legally entitled to use the "Dr."

There was a major fuss some years back at the East Kent Hospital in Canterbury. The administrators tried to pass an edict saying "you can only call yourself Doctor if you're a medical doctor". It very rapidly got dropped - the Ph.D's on staff said "hang on a sec, we have a *legal* entitlement* to use 'Dr', medical people don't. You try and stop us using it, we'll get the courts to stop the medical people from using it".

And one of my friends, when she was a student doctor, commented on the confusion caused by one of her fellow students, who was a Ph.D.

It dates back, as the previous comment says, to when Physicians *were* doctorally qualified. Today's medical doctors aren't Doctors, they're Apothecaries (chemists, ie pharmacists). Because they dispensed medicine, and provided medical advice to the majority of people who couldn't afford a Doctor's advice, they rose in status and acquired the honorific "doctor". One of my doctor friends joked about how doctors have an apprenticeship and are "tradespeople" not "professionals".

Cheers,
Wol