Agency (sociology) experiences, and the perceptions held by the society and the individual, of the structures and circumstances of the environment one is in and the position they are born into. Disagreement on the extent of one's agency often causes conflict between parties, e.g. parents and children. The concept of agency has existed since the Enlightenment. René Descartes' phrase Cogito ergo sum stated that anyone who could think is an agent , and any agent capable of knowing that it can think was a subject. Immanuel Kant expanded on this theory by stating that the only way to truly become self-aware is
Cogito, ergo sum "Meditations", Descartes phrases the conclusion of the argument as "that the proposition, "I am, I exist," is necessarily true whenever it is put forward by me or conceived in my mind." ("Meditation" II) At the beginning of the second meditation, having reached what he considers to be the ultimate level of doubt—his argument from the existence of a deceiving god—Descartes examines his beliefs to see if any have survived the doubt. In his belief in his own existence, he finds that it is impossible to doubt that he exists. Even if there were a deceiving god (or an evil demon),