The problem of generality appears when we take the reliability theory of justification in its simple form. This problem can be avoided if we require (as Goldman does) that besides actual reliable processes there must not be available other reliable processes which would lead us to reject, the present belief. For a process to be reliable it is necessary that it preserves the truth. If it would lead us to believe true propositions as well as false ones then it is not reliable. Reliability theory of justification is a theory of justified belief and not a theory o justified believer. This suffices to show that realibility is both a sufficient and necessary condition of justification.
