Compare mathematics and the political sciences - it's quite striking. In mathematics, in physics, people are concerned with what you say, not with your certification. But in order to speak about social reality, you must have the proper credentials, particularly if you depart from the accepted framework of thinking. Generally speaking, it seems fair to say that the richer the intellectual substance of a field, the less there is a concern for credentials, and the greater is the concern for content.
Four years of Jimmy Carter gave us two titanic Reagan landslides, peace and prosperity for eight blessed years - and even a third term for his feckless vice president, George H. W. Bush.