ABSTRACT
Logic provides a useful tool when one wants to know whether an explanation is true. An argument that something is not a cause is always subject to an important qualification. What makes an experimental investigation different from the methods is that it is explicitly making changes in order to determine whether something is the cause. The opposite of the difficulty of no cause occurs when the methods leave people with too many causes. This chapter stresses that the direct and the inverse method of agreement must be used together. It focuses on the method of concomitant variation. There are numerous weaknesses in the method of difference. The chapter argues that the contributory causes are to relax the considerations used in the methods so as to require only a correlation between the cause and effect. The general strategy underlying the demonstration of scientific laws, theories, and models is reviewed in the chapter.
