From the preceding examples, we may get some idea of the change in perspective that may occur in our reading and interpretation of the philosophical works of antiquity when we consider them from the point of view of the practice of spiritual exercises. Philosophy then appears in its original aspect: not as a theoretical construct, but as a method for training people to live and to look at the world in a new way. It is an attempt to transform mankind. Contemporary historians of philosophy are today scarcely inclined to pay attention to this aspect, although it is an essential one. The reason for this is that, in conformity with a tradition inherited from the Middle Ages … they consider philosophy to be purely abstract-theoretical activity.
—Pierre Hadot, Philosophy as a Way of Life