In the classical sense, a philosopher was someone who lived according to a certain way of life, focusing on resolving existential questions about the human condition, and not someone who discourses upon theories or comments upon authors. Typically, these particular brands of philosophy are Hellenistic ones and those who most arduously commit themselves to this lifestyle may be considered philosophers. A philosopher is one who challenges what is thought to be common sense, doesn’t know when to stop asking questions, and reexamines the old ways of thought.
In a modern sense, a philosopher is an intellectual who has contributed in one or more branches of philosophy, such as aesthetics, ethics, epistemology, logic, metaphysics, social theory, and political philosophy. A philosopher may also be one who worked in the humanities or other sciences which have since split from philosophy proper over the centuries, such as the arts, history, economics, sociology, psychology, linguistics, anthropology, theology, and politics.
The separation of philosophy and science from theology began in Greece during the 6th century BC. Thales, an astronomer and mathematician, was considered by Aristotle to be the first philosopher of the Greek tradition.
While Pythagoras coined the word, the first known elaboration on the topic was conducted by Plato. In his Symposium, he concludes that Love is that which lacks the object it seeks. Therefore, the philosopher is one who seeks wisdom; if he attains wisdom, he would be a sage. Therefore, the philosopher in antiquity was one who lives in the constant pursuit of wisdom, and living in accordance to that wisdom. Disagreements arose as to what living philosophically entailed. These disagreements gave rise to different Hellenistic schools of philosophy. In consequence, the ancient philosopher thought in a tradition. As the ancient world became schism by philosophical debate, the competition lay in living in manner that would transform his whole way of living in the world.
Among the last of these philosophers was Marcus Aurelius, who is widely regarded as a philosopher in the modern sense, but personally refused to call himself by such a title, since he had a duty to live as an emperor.