 The third mode (I.444c–445b) contrasts the being of actual things with the “non-being” of potential or possible things still contained, in Eriugena’s memorable phrase, “in the most secret folds of nature” (in secretissimis naturae sinibus). This mode contrasts things which have come into effect with those things which are still contained in their causes. According to this mode, actual things, which are the effects of the causes, have being, whereas those things which are still virtual in the Primary Causes (e.g., the souls of those as yet unborn) are said not to be.