I’m interested in the evidence for this? I could see how doctors in the 1800s would have had to legitimize themselves since their duties were basically to provide first aid more or less, with some treatments that might help or kill the patient (bloodletting, for example).
However, the idea of a doctor is that he or she is an expert in their field. A PhD in biochemistry means the person is an expert in biochemistry. You would go to them for questions about it, and you’d trust what they tell you without much doubt. Similarly, MDs are experts in medicine. You go to them for questions about health, disease, and treatment. You’d trust their advice and answers.
Socially, no a PhD in chemistry is not seen as “higher” than an MD.
I'm pretty sure M.Ds stole the term "Doctor" from Ph.Ds to legitimize themselves. Kinda like how nurses are doing now to M.Ds..
Anyway, very few of the smartest people I know want to become doctors. Occupation isn't a way to measure somebody's worth. Even it did, to be honest, I think Ph.Ds tend to be higher on the totem pole than M.Ds anyway.
While the PhD degree came first, medieval European universities basically existed to train physicians, lawyers, theologians and priests. Natural sciences and engineering joined the fray but the term “natural philosophy” still referred to what we now know as “STEM” for centuries. “Doctor” as a Latin term just means “teacher” and part of the terminal degree was receiving a license to teach the subject. Early PhDs didnt even do any research or produce dissertations for the first several centuries, they simply had to pass examinations to certify them as knowledgeable in their subject. So Doctor of Medicine was the original doctorate but was not really a professional degree in the way that it is now as quite a lot of people without degrees practiced what we might call today Medicine or surgery at a professional level (barber surgeons, alienists) by becoming an apprentice to a member of the trade. It took quite a few centuries for the whole enterprise to become recognizably professional across Europe, probably not until the late Middle Ages. Even then, there was a massive turf war between the priests and physicians as to who was best equipped to treat some diseases, particularly cognitive and mental ones like hallucinations/chorea/schizoid disorders/depression (see Andrew Scull's excellent book
Madness and Civilization). This was the result over arguments about whether humans were entirely material, or not, or something in between; whether or not certain mental and physical disorders were caused by possession or sin or distraction or sloth or "humors".
Also, medieval doctors didn't just do "basically first aid" and bloodletting. Don't get me wrong, medieval and victorian medicine especially surgery was pretty barbaric (see
The Butchering Art), but that doesn't mean that people werent making a concerted effort to make discoveries and learn things about the human body. In China, around 200
BC systematic forms of medical education were already being taught (the earliest textbook being the
Yellow Emperor's Classic of Internal Medicine). Of course, a lot of the theory here was not based on experimental or evidentiary science (a lot of Traditional Chinese Medicine is based on Chinese Cosmology, believe it or not, which was a lot more robust itself as a science than TCM in relative terms) but it was a theory. The classical Islamic world is responsible for retaining most of the information from classical western civilization and reintroducing it back to Europe in the Middle-Ages. At that time, Islamic natural philosophers like Ibn-Sina (Avicenna in the Romanticized form) were publishing books on anatomy and physiology and case studies of patients using methods that would be closer to modern science than would be seen in Medieval Europe for some centuries. India had medical universities thousands of years before Europe, etc.
tl;dr: PhD came first but MDs and PhDs were not understood to be doing anywhere near similar things until the twentieth century and they would have never been in competition for credibility in any way.
The modern “MD” professional degree originated in 17th century Scotland and was imported to North America by first Columbia P&S and later Harvard, Yale.
