Adult education refers to programs that prepare scholars to teach, train, or coach adult learners. Adult educators may teach courses to prepare adults for the GED or other high school equivalency or provide professional development courses for working professionals.

The PhD is a doctoral degree, specifically called a "doctor of philosophy" degree. This is misleading because PhD holders are not necessarily philosophers (unless they earned their degree in philosophy!). That said, PhD recipients are able to engage in thought experiments, reason about problems, and solve problems in sophisticated ways.