1. A method for learning in a valuation-based learning system, comprising an act of manipulating a computer to perform acts of: receiving a plurality of inputs, each input being input evidence corresponding to a variable in a Dempster-Shafer Reasoning System, wherein the Dempster-Shafer Reasoning System is a network of interconnected nodes, with each node being representative of a characteristic of a problem domain; optimizing a discount weight for assigning to each of the inputs; generating a basic probability assignment (bpa) using the Dempster-Shafer Reasoning System, and where the bpa is an output for use in determining a solution of the problem domain; determining a solution to the problem domain using the bpa; and providing the solution to a user.