ABSTRACT
Darwin’s theory of natural selection had an important influence on the Neogrammarians. Like Darwin, they believed that diachronic change was the result of selective pressures on organisms from the environment operating on random variation within a population. Learning theory must provide an account of how the learner’s search through the set of possible combinations of parameter values takes place, and of how certain values are chosen over others. Genetic algorithms mimic natural selection by representing hypotheses about a problem in a way that is similar to the way in which genetic material is represented. Hypotheses are then tested against the problem space, with the most fit hypotheses contributing to the formation of new hypotheses via reproduction. Clark provides a crude definition of improvement based on the ability to parse input sentences in terms of failed parses. A shifted system of parameter settings can be thought of as a marked system.
