Logicians and philosophers of science (e.g. Carnap, Popper) have taken
the logical content of a wff to be the class of its logical
consequences.  This has many unintuitive results and has particularly
hampered research in philosophy of science (e.g. in defining
hypothetico-deductive confirmation, verisimilitude, empirical
significance, irrelevance and probabilistic conformation.).  An
alternative account of logical content is proposed.  Definitions, both
syntactic and semantic, allowing for a completeness proof for
propositional languages and a definition for a quantificational language
with identity, are given.  The later makes use of a substitutional
interpretation of the quantifiers.  Open problems concerning the
definitions for more advanced languages are presented.