What is the higher degree of doctor?

There isn't a single "higher" degree of doctor universally agreed upon. It depends entirely on the field and the specific degree. For example:

* In medicine: A medical doctorate (M.D. or D.O.) is considered the terminal professional degree. While further specialized training (fellowships) exists, they don't represent a higher degree in the same way a Ph.D. builds upon a master's.

* In other fields (e.g., philosophy, engineering, etc.): A Doctor of Philosophy (Ph.D.) is generally considered the highest academic degree. Some fields have other doctoral degrees that are equivalent (e.g., Doctor of Science, ScD).

So, there's no single answer. The "higher" degree is context-dependent and depends on what you mean by "higher" – academic achievement or professional standing.