and thirst and sexual desire, and the higher demands for fighting and playing and acquiring, for seeking power and social influence, as a psychologist would discuss them, referring them to biological and physiological conditions and explaining them causally.  Yet as soon as they come to their real problems and enter into the interpretation and meaning of these economic energies, they naturally slide back into the historical, economic point of view and discuss the economic relations of men without any reference to their psychologizing preambles.  The application of the psychological, scientific method to the true economic experience is therefore not secured at all in this way.  The demands and volitions which they disentangle are not the ones which the psychophysiologist studies, because they are left in their immediate form of life reality.  They are accordingly inaccessible to the point of view of experimental psychology, and nothing can be expected from such interpretative discussions of the economists for the psychotechnics at which the psychologist is aiming.  Even where the political economists deal with the problems of value in exact language, nothing is gained for the kind of insight for which the psychologist hopes, and the psychologists must therefore go on with their own methods, if they are ever to reach a causal understanding of the means by which a satisfaction of the economic demands may be effected.

So far the psychologists have not even started to examine these economic feelings, demands, and satisfactions with the means of laboratory psychology.  Hence no one can say beforehand how it ought to be done and how to gain access to the important problems, inasmuch as the right formulation of the problem and the selection of the right method would here as everywhere be more than half of the solution.  It must be left to the development of science for the right starting-point and the right methods to be discovered.  Sometimes, to be sure, the experiment has at least approached this group of economic questions.  For instance, the investigations of the so-called psychophysical law have often been brought into contact with the experiences of ownership and acquirement.  The law, well known to every student of psychology, is that the differences of intensity in two pairs of sensations are felt as equal, when the two pairs of stimuli are standing in the same relation.  The difference between the intensities of the light sensations from 10 candles and 11 candles is equal to that from 50 candles and 55 candles, from 100 candles and 110, from 500 candles and 550:  that is, the difference of one additional candle between 10 and 11 appears just as great as the difference of 50 candles between 500 and 550.  The psychologists have claimed that in a corresponding way the same feeling of difference arises when the amounts of possessions stand in the same relation.  That is, the man who owns $100 feels the gain or loss of $1 as much as one who owns