 It is not completely clear what “the principle [principium]” at stake is, but given its qualification as “known through itself and in itself”, it may refer to God and indicate Spinoza’s understanding of Descartes’ rather nuanced view—in his Second Set of Replies—according to which God does not need a cause in order to exist, but there is a reason why God does not need a cause (AT VII: 164–65; cf. Carraud 2002: Ch.  2).[4]