 The arguments considered in  §1.2  constitute the typical motivation for realism, which is the stance that we take for granted here. They may be configured as an abductive inference to the best explanation (Swoyer 1999). Thus, of course, they are not foolproof, and in fact nominalism is still a popular view, which is discussed in detail in the entry on  nominalism in metaphysics,  as well as in the entry on  tropes.  Conceptualism appears to be less common nowadays, although it still has supporters (cf. Cocchiarella 1986a: ch. 3; 2007), and it is worth noting that empirical research on concepts is flourishing.