Ever since Frege, philosophical semantics pushes toward a theory of meaning based on reference and truth, attempting to show how our linguistic statements are not private, psychological, or culturally relative assertions, but capable of referring objectively to the real world. How does Frege argue for the distinction between sense and reference, and how does this relate to truth in his theory? What are the problems associated with this approach, as pointed out by Russell and others? What is the achievement of a theory of descriptions as defining reference?