 Emergentists are also sometimes referred to by Essentialists as ‘empiricists’, but they either use the Emergentist label for themselves (Bates et al. 1998, O’Grady 2008, MacWhinney 2005) or call themselves ‘usage-based’ linguists (Barlow and Kemmer 2002, Tomasello 2003) or ‘construction grammarians’ (Goldberg 1995, Croft 2001). Newmeyer (1991), like Tomasello, refers to the Essentialists as ‘formalists’, because of their tendency to employ abstractions, and to use tools from mathematics and logic.