According to a preferred embodiment, a concept learning system and method is used for classifying instances, which, for example, may include web pages or text documents. An instance is input into the system. One or more candidate concepts are recalled from a set of candidate concepts. For each recalled concept, a classifier that corresponds to it is applied to the instance to determine if the recalled concept is related to the instance. Samples are selected from a training set. A learning method is applied, and a set of candidate concepts are updated according to the results from applying the learning method.