however, agreement may indicate simply a copying of errors. Failure to approximate the same results on the part of independent students of similar problems indicates fallacious thinking on the part of one or both. The lack of any large body of sociological truth verified and accepted by independent students is strong evidence against the soundness of the bulk of sociological thinking.

If it is possible to check the conclusions of casual thinking against impartially selected facts the results are capable of proof or disproof. To do this usually involves, however, the use of the more strictly scientific methods described below. The absence of any adequate checks upon most theorizing is a great social weakness.

It should be acknowledged in passing that the present paper is a product of the common-sense method. The ultimate test of its value will be the results achieved by the methods which it proposes.

Deductive reasoning must of course be used in conjunction with any of the inductive methods. The tremendous liability to logical fallacy, however, places deduction in a class closely related to the casual method. The conclusions of logic are of value only when closely checked by criticism and experiment. The chief function of the common-sense and deductive methods is to provide hypotheses to be tested out by more rigorous scientific methods.

The historical method is characterized by its use of documents as its basic materials. The documents used are almost entirely the result of the common-sense method as applied by contemporary observers. That is to say, they are the records of the experiences, the acts, and the observations of individuals not attempting rigid definitions, classifications, enumerations, measurements, or correlations, and not seeking to make exhaustive investigations. In some cases-particularly in connection with legal documents— considerable accuracy may be predicated of the data involved, but in proportion as comprehensiveness and precision are introduced into the original documents the method ceases to be typically historical and becomes more properly classifiable under the museum or statistical methods. Although based upon casual materials, the historical method is a great advance over the casual method in that the attempt is made to take into account all of the pertinent

documents in arriving at conclusions. If the historian is openminded and industrious, he may eliminate much of the error of his original materials by comparisons of the observations of independent students. If he is biased by patriotism or prejudice he may, of course, introduce his own errors of selection into his results.

Even with the best intentions, however, certain handicaps are inherent in the historical method. The original documents tend to be selective in the data which they report, for they reflect for the most part the viewpoints of the educated and privileged classes and are colored by the superstitions, prejudices, and limitations of the times when they were written. The casual observers who produced the documents on which history is based were for the most part unable to observe with complete impartiality, because of their lack of training and of scientific information. They did not know what to look for or where to find it. Modern historians have been developing technique for guarding against these errors. It is a development of the historical method which Small has suggested as the ideal procedure in sociological research. His plan would be for a group of specialists in the various social sciences all to investigate concurrently the same historical epoch, such, for example, as the French Revolution. The method used by Thomas in The Polish Peasant in Europe and America is perhaps allied more closely to the historical than to any other of the methods listed above. Its scientific value testifies to the rich rewards awaiting the student who is willing to collect and compare social data systematically and impartially. Such work is useful to the degree that it is precise in definition, that it gathers impartially all pertinent data, and that it discovers the degree and significance of the correlations between the variables involved. Any procedure which adds accuracy, impartiality, and comprehensiveness to the processes of definition, classification, measurement, enumeration, and correlation, promotes progress toward scientific methods.

The museum or census method, as herein defined, is concerned primarily with definition, classification, and enumeration of items. Many of the biological sciences proceed chiefly by the museum method. Geology and paleontology utilize it extensively.

The Meaning of Social Science, pp. 156 ff.

In the social sciences the museum method has been strongly in evidence in ethnology and anthropometry. The great bulk of sociological statistics, including the United States census and many other government reports, may be classified under this head, since their chief end is description, classification, and enumeration. Social surveys have frequently furnished examples of this method. Some social surveys attempt to establish correlations but they do so chiefly by common-sense methods.

From the standpoint of pure science doubtless the work accomplished by the museum method appears to be worth while for its own sake. From the standpoint of utilitarian or applied science the classifications of the museum and of the census can be justified only in so far as they facilitate the higher purpose of correlation of developing scientific laws through which phenomena may be controlled for human ends, or through which human conduct may be better adjusted to the uncontrollable phenomena of nature.

The laboratory or experimental method has two fundamental characteristics: first, the development of apparatus for the accurate observation, measurement, recording, and enumeration of data; and second, the development of methods for controlling all variables except the one under investigation. Illustrations of the apparatus developed in the laboratory occur in profusion: micrometers, microscopes, telescopes, microphones, minutely accurate weighing scales; delicate instruments for measuring heat, electrical current, earthquake shocks thousands of miles away, the intensity of light or the pressure of blood in human arteries; kymographs for recording automatically various types of pulsation; the moving picture and the phonograph for recording sights and sounds; the calculating machine, and the assorting and tabulating machines-these and innumerable other instruments illustrate the development of laboratory apparatus for eliminating the shortcomings of the human sense organs and nervous system as the instruments for measuring, recording, classifying, and enumerating data.

The laboratory method of studying the correlation between two variables by keeping all other pertinent variables constant may be illustrated by the procedure of an engineer interested in the effect of lime upon the characteristics of concrete. In order

to study the matter he carried out several thousand experiments in which the other variables which affect the qualities of cement, such as the richness of the mixture, the fineness of the gravel used, the conditions under which the concrete hardened, and the like, were kept constant at various combinations while the proportion of lime was varied. From the resulting data it was possible to say that under specified conditions lime in specified quantities has a certain accurately determined effect upon the qualities of concrete. This, of course, is the typical laboratory procedure-to control the variables involved in a problem, and to observe the changes which occur in one variable with given changes in a second variable when all other pertinent variables are kept constant at known intensities.

It is the laboratory, or experimental, method, doubtless, which stands out most clearly in the mind of the average man when he thinks of science. This method has been the basis of the much heralded scientific triumphs of modern times. The Industrial Revolution started with inventions which resulted from experimental research, and modern industry, whether in manufacturing, mining, agriculture, or transportation, depends upon the findings of the chemical, engineering, metallurgical, agronomical, or electrical laboratory.

Not only in its effects but also in its origins the laboratory method has been largely utilitarian. In its rudimentary state, of course, the method did not imply the possession of the accurate instruments and highly controlled conditions of modern times. The primitive laboratory was quite likely to be a woodshed or a rear lot. In its essence experimentation arises from the trial-anderror method which is instinctive not only in human mental processes but in the reactions of mice, chicks, guinea pigs, and even angleworms. Indeed, the amoeba, thrusting out experimental pseudopodia, is engaged in rudimentary scientific investigation of its environment. The amoeba, moreover, is more scientific than many a human student, for the amoeba sticks closer to the facts and avoids the logical errors of generalizations from biased data.

Sociology, unfortunately, can take relatively little advantage of the laboratory or experimental method. This is the case for

three principal reasons: First, experiments in human welfare often take so long that progress is infinitely tedious. One would have to wait a lifetime, in many cases, in order to get the results of a single experiment. Second, the number of variables is so great that it is exceedingly difficult to be sure that uncontrolled factors are not responsible for the results. Is the present great Russian experiment in communism, for example, a failure (if it is a failure) because its economic theories are unsound, or because of the allied blockade and the fostering of wars against her on the part of Poland and other countries? Or is it a success (if it is a success) because its economic theories are sound, or because the extraneous factor of external aggression amalgamated the people in spite of the economic complexion of the government? Questions of this sort inevitably arise in connection with the Social Unit Experiment, Helicon Hall, the Amana Community, or any other sociological experiment.

The third reason for the relative unavailability of the laboratory method in sociology is that human nature makes the control of many of the variables related to human welfare impossible. It is socially non-feasible, for example, to carry out experiments in human breeding. It is extremely difficult to control the liberty of any individual so successfully as to be sure that he or she is conforming to the conditions of a given experiment.

For the foregoing three reasons social science, if it is to experience the tremendous progress and development which have attended the introduction of laboratory procedure into such sciences as physics, chemistry, bacteriology, and psychology, must have recourse to some method which offers the precision, objectivity, and universality of the experimental method under the conditions involved in social research. These requirements are met by the statistical method.

In connection with the suggestion of statistics as the scientific method for sociology it should be observed that Comte and Ward both averred the impracticability of reducing social data to mathematical terms, which is exactly what it is proposed herein to do. As contrasted with Comte and Ward, Giddings in his definition of sociology refers to it as a "science statistical in its method."