ABSTRACT
MILL'S five Methods of Experimental Enquiry1 are unsatisfactory in various ways and have been to a considerable extent honoured in the breach by scientists; Johnson gave Four Figures of Demon strative Induction,2 but, though they differ markedly from Mill's Methods, they are probably just as far removed from scientific inference; Stebbing improved on all these by enunciating four Special Principles of Causal Determination,3 which, however, are not wholly satisfactory because they do not take sufficient account of the possible complexity of apparently simple factors or of the plurality of causes and effects or of the distinction between the necessary and the sufficient. Certain features of Johnson's Figures can yield matter that is relevant to scientific procedure, but it is simpler to treat the subject independently. What is required is to tabulate the criteria that are actually found in or implied by scientific procedure. What follows is, therefore, an attempt to give a new treatment from this point of view.
