1. A method, in a data processing system, for evaluating a link between information concept entities, comprising: receiving, by the data processing system, a set of evidential data specifying a plurality of information concept entities; generating, by the data processing system, a link between at least two information concept entities in the set of evidential data; evaluating, by the data processing system, the set of evidential data with regard to whether or not the set of evidential data supports or refutes the link, wherein the evaluation of the set of evidential data comprises analyzing language of natural language statements in the set of evidential data to identify certainty terms within the natural language statements; calculating, by the data processing system, a confidence value for the link based on results of the evaluation of the set of evidential data; and generating a knowledge output, by the data processing system, based on the link and the confidence value associated with the link.