28 THE AMERICAN JOURNAL OF SOCIOLOGY
Whether this conception is ever proved or not, the case at present is that, although we speak freely of causation, of original causation, we know nothing, and what we call causes are only occasions. Particular combinations of phenomena furnish the occasions for the causal Power resident in nature to manifest particular results. When different streams of phenomena issuing from the source of being meet, the current of manifestations consequent upon their union is often different from either of the confluents. Each "higher" process appears as a more complex resultant of such unions of simpler processes. And, so far as we can see, the primordial processes of nature are continuous manifestations of power which, with their countless combina- tions and recombinations, make up the vast diversity of the phenomenal world. That which we call the study of causes, which is the soul of science, is observation of the changes that ensue when phenomena have met. Phenomena that meet, and from the union of which other phenomena emerge, are what we call "causes." They are not forces, but conditions conditions of change in the manifestations that arise from the operations of the force already present in the phenomena that combine. The combining phenomena may be uninteresting, and our interest and attention first be fixed by the resultant. When we seek to explain the resultant process, we do so by discovery of those conditions which we name "causes," although to identify them contributes no knowledge of the original causation of the inter- esting phenomenon which we have thus, as we say, " explained." The study of causes that is possible to science is observation of the phenomena that unite to form the conditions of new phe- nomena. When again and again we have observed phenomena of a certain kind, arising in the presence of certain conditions, we affirm that these conditions contain the causes of such phe- nomena. To know that phenomena of the kind thus explained have been observed countless times to arise in presence of these conditions, and never in the absence of any of them, that the phenomena have varied as these conditions have varied, and dis- appeared with the disappearance of each of these conditions, when all the others were present, is to have established the scien-
