elementary æsthetic feelings, and last of all with the composition of the emotions and volitional processes out of their elements. Starting from these single more or less complex processes of consciousness, this character of regularity applies above all to the temporal succession of the processes. The generalisations of the old association psychology were absolutely inadequate, and its chief mistake lay, not so much in postulating laws too hastily, as in the fact that it did not attempt to penetrate deeply enough into the laws underlying the association processes by means of an analysis of the same. A last and conclusive testimony for this lawful character of psychical phenomena is given by the apperceptive combinations, whose specific products (of course quite dependent upon the laws of association), are the combinations of the thought-processes, as we have seen above. There can be no more striking proof of the absurdity of the above-mentioned theory of the lawlessness of psychical phenomena as the consequence to which it would lead us. For it would lead to the conclusion that the conception of law itself was contrary to law. This conception is in fact nothing more than one of the results of those psychical thought-combinations, the lawful nature of which is questioned. It would lead us too far here to go into the profusion of psychical laws. The general character of them has been suggested in our chapters on association and apperception. In the natural sciences there are more general fundamental laws that rise above the separate particular laws, and these we may call the principles of investigation, in so far as they are general requirements to which investigation has to conform. In the same way we can set up fundamental laws in psychology which are not included in the separate regularities of phenomena, because they can only be gained from a general view of the whole of such phenomena. In physics, for example, the above-mentioned example of the law of inertia is a universally valid law. The same claim is raised in a wider scope by "the law of the indestructibility of matter," and by the near-related "principle of the conservation of energy." Are there, we naturally ask at once, psychological principles of similar universal validity?