Wolfgang Schwarz

A new kind of Neo-Fregeanism?

Frege argued that number concept are, in the first place, second-order predicates. When we talk about numbers as objects, we use a logical device of "nominalization" that introduces object-level representations of higher-level properties. In Grundgesetze, he assumed that every first-order predicate can be nominalized: for every first-order predicate F, there is an associated object – the "extension" of F – such that F and G are associated with the same object iff ∀x(Fx ↔︎ Gx). The number N is then identified with the extension of 'having an extension with N elements'. Unfortunately, the assumption that every predicate has an extension turned out to be inconsistent, so the whole approach collapsed.

Lewis on Quasi-Realism

In "Quasi-Realism is Fictionalism" (Lewis (2005)), Lewis seems to suggest that Blackburn's quasi-realism about moral discourse is a kind of fictionalism. The suggestion is bizarre. Has Lewis made silly mistake? (Spoiler: No.)

Let's compare what quasi-realism and fictionalism say about moral discourse.

Blackburn's quasi-realism (as presented, e.g., in Blackburn (1984, ch.6) and Blackburn (1993)) is a brand of expressivism. According to Blackburn, moral statements like (1) don't serve to describe special facts, but to express moral attitudes.