As a universal history of philosophy, the history of philosophy must become one great unity.

The great philosophers and the great works are standards for the selection of what is essential. Everything that we do in studying the history of philosophy ultimately serves their better understanding.

The history of philosophy is not, like the history of the sciences, to be studied with the intellect alone. That which is receptive in us and that which impinges upon us from history is the reality of man's being, unfolding itself in thought.

Philosophy is tested and characterised by the way in which it appropriates its history.

The history of philosophy is to a great extent that of a certain clash of human temperaments.

The history of all previous societies has been the history of class struggles.