Validity of Practical Inference Berislav Zarnic Abstract: The paper develops a dynamic framework suitable for analysis of practical reasoning. The application of functional approach in dynamic semantics confirms the results obtained in philosophical analyses of practical inference, regarding, in particular, defeasibility, undetachability and distinctive quality of conclusion. Contrdictory results of proposed tests of validity and conflicting intuitions on valid forms of practical inference are reconciled. Keyword(s): dynamic semantics, inference, validity