World history can look at the big picture. Instead of zeroing in on what happened in select states or regions during a historical period, it often examines what occurred globally. The emphasis of this field of study may be on the themes and patterns that have shaped the planet.

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.