I suppose it is generally agreed that the task of science is to render intelligible, or in some way account for, the objects and events of our experience. Usually we say that the job of science is to explain. While this is a satisfactory formulation for most purposes, it hides a difficulty. What is meant by “explanation”? The many interpretations of this word divide scientists and philosophers of science into sharply differentiated schools. For some “explanation” means answering the question, Why?; for others it means merely describing. For some it means finding causes; for others it means finding effects or abandoning entirely the search for causes and effects. For some it means employing quantitative methods only; for others it means supplementing or replacing quantitative methods by qualitative. For some it means interpreting or understanding; for others it means merely adjusting oneself in a practical way.