| Middle Platonists | Expanded and dogmatized upon Plato’s concept of the realm of ideas/forms as more substantial than their individual physical expression. |
| Sophists | Enamored with the successful execution of rhetorical argumentation (sometimes regardless of the particular position taken in the argument). |
| Cynics | Contended for a more naturalistic way of pious living, often engaging in shocking verbal and physical feats to make their points. |
| Epicureans | Believed that all that exists were miniscule packets of matter (atoms), that humans were entirely composed of aggregate matter (thus ceasing to exist upon death), and that life was consequently about maximizing earthly pleasure through friendships and enjoyment of life. |
| Stoics | Argued that the world was fundamentally the expression of a rational force (the logos), and that harmonious good living required an exaltation of reason over spontaneous emotions in all of life. |