Philosophical theories are theories that are philosophical, rather than purely scientific by nature. Meanwhile, philosophical concepts can be loosely describes as ideas or “concepts” that are philosophical in nature.

Generally, a concept is a single idea, a theory is an explanation of how something works, and philosophy is simply the study of that which we can’t know for sure (see the branches of philosophy.).

So then, for our purposes, philosophical theories and concepts is simply a broad category that contains all non-scientific theories worth discussing.

TIP: For a great explainer on the basics of Philosophy see Tamar Gendler: An Introduction to the Philosophy of Politics and Economics by Big Think.

NOTE: Some scientific theories that spark metaphysical philosophical questions are categorized here (as well as under their respective scientific fields). Learn more about scientific theories.

Essentialism vs. Existentialism

Essentialism is the idea that everything has an essence (something that “makes it, it”). Existentialism says there is no essence (no intrinsic meaning that can be confirmed by the senses or reason).

Hume’s Fork Explained

“Hume’s fork” describes how we refer to Kant’s critique of Hume, who separated knowledge into two types: facts based on ideas and facts based on experience.

Game Theory is the Study of Games


Game theory involves games, but it isn’t the study of games. It is the study of mathematical models of conflict and cooperation regarding decision making.