Of all our knowledge, the first is of the existence of our soul; all our thoughts are incontestable demonstrations of this, since there is nothing more obvious than that what actually things, is actually something. But if it is easy to know the exisence of our soul, it is not so easy to know its essence and nature.
Malebranche, The Search after Truth, Book VI, Part II, Chapter 6 (LO 480)
