The Weltanschauung or world view of Nancy Cartwright, scientist and philosopher, will be explored today.   Cartwright brings into question two presuppositions of all science:  causal inference and objectivity.  Her publications include:  Causal Powers: What Are They? Why Do Need them?  What Can And Cannot Be Done With Them?;  Hunting Causes and Using Them: Approaches in Philosophy and Economics; The Dappled World: A Study of the Boundaries of Science;  Nature's Capacities and their Measurement;  and How the Laws of Physics Lie.