Evolution and Systems Theory

The value of a scientific theory lies in its potential for stimulating further thought and research. Ideally, a theory should be experimentally testable. If not, as is the case with historical theories such as biological evolution, it should at least explain the observable facts in a logical and consistent fashion. In so doing it will perform another sort of function, that of indicating which facts are missing and should be discovered. The theory of biological evolution has served this function on an enormous scale by providing the stimulus during the latter half of the 19th century and the first years of the 20th for collecting all the available facts concerning the comparative anatomy of living and extinct forms of life as well as the description of embryonic development in living plants and animals.