Saint Basil’s letter to , highlights the distinction between the key terms and . The distinction is the same as that of the general and the particular, as for instance between a ‘living thing’ such as the animal and the particular man. Thus, when it comes to the Godhead - the Holy, and Undivided Trinity - St Basil notes that we confess one essence (so we do not have a variant definition of existence) while confessing a particular so we do not confuse the persons of the one Godhead. We must have distinct perceptions of these Three Persons, of their characteristics as Father Son and Spirit, which forms our coherent perception of the ‘common’ Godhead. So these two terms, for St Basil, provide us with the essential link between God’s unity of Persons, but also their diversity of characteristics.