Its not that complicated, a PH.D is a Philosophy doctorate whether you attain it in medicine, economics, history, politics, geography, mathematics, science, following a specialist pathway going onward to a professorship, yep 30 years of specialising. In most reputable Universities/colledges your lecturers all have a PhD in their feild or are working toward it by publishing their work. If you sit on the rght wing but cannot see the heirarchy of intellect, you might be over looking the cream for the milk.