  The One is such a principle.  Plotinus found it in Plato’s Republic where it is named ‘the Idea of the Good’ and in his Parmenides where it is the subject of a series of deductions (137c ff.).  The One or the Good, owing to its simplicity, is indescribable directly.  We can only grasp it indirectly by deducing what it is not (see V 3. 14; VI 8; VI 9. 3).  Even the names ‘One’ and ‘Good’ are fautes de mieux. Therefore, it is wrong to see the One as a principle of oneness or goodness, in the sense in which these are intelligible attributes. The name ‘One’ is least inappropriate because it best suggests absolute simplicity.