Dispositions and Definitions

Abstract

1. By an (explicit) definition of a descriptive predicate ‘Q’ with one argument we understand a sentence of the form

$$ \left( {D:} \right)Q\left( x \right) \equiv ...x... $$

where at the place of ‘...x...’ a sentential function—called the definiens—stands which contains ‘x’ as the only free variable. For several arguments the form is analogous. We will say that a definition D is based upon the class C of predicates if every descriptive symbol occurring in the definiens of D belongs to C. If the predicates of a class C are available in our language we may introduce other predicates by a chain of definitions of such a kind that each definition is based upon C and the predicates defined by previous definitions of the chain.