the misfortune of this important addition to psychology, that it shows that previous workers in this field of inquiry have at times been laboring in the dark to solve problems like in kind with the famous difficulty of accounting for the supposed fact that the weight of a vessel of water is not increased by the addition of a live fish. For instance, should Mr. Spencer be right, the celebrated theory of the Will, elaborated by Prof. Bain, the able representative of the individual-experience psychology, becomes a highly-ingenious account of what does not happen. Thus, the new doctrine can be accepted only at the expense of giving up much of what has hitherto passed for mental science.
The following sentences will serve to indicate Mr. Spencer's position: "The ability to coördinate impressions, and to perform the appropriate actions, always implies the preëxistence of certain nerves arranged in a certain way. What is the meaning of the human brain? It is that the many established relations among its parts stand for so many established relations among the psychical changes. Each of the constant connections among the fibres of the cerebral masses answers to some constant connection of phenomena in the experiences of the race. . . . Those who contend that knowledge results wholly from the experiences of the individual, ignoring as they do the mental evolution which accompanies the autogenous development of the nervous system, fall into an error as great as if they were to ascribe all bodily growth and structure to exercise, forgetting the innate tendency to assume the adult form. . . . The doctrine that all the desires, all the sentiments, are generated by the experiences of the individual, is so glaringly at variance with facts, that I cannot but wonder how any one should ever have entertained it." The circumstances which account for the existence of the individual-experience psychology, and which enable it still to hold out as a rival of the more advanced form that Mr. Spencer has given to the science, are these: (1) the immaturity of the human infant at birth; (2) the lack of precise knowledge with regard to the mental peculiarities of the lower animals; (3) the still popular notion that the human mind does not resemble the mental constitution of the animals; that it is of a different order. Of course this last is nowadays little more than a popular superstition, nevertheless it can be taken advantage of: and an argument to the effect that the mental operations of the animals are, to all appearance, so very different from the workings of the human mind that they can supply nothing more than a worthless, if not a misleading analogy, has a very specious and scientific look about it in the eyes of those who are not very well acquainted with the subject. Our ignorance of animal psychology may be still more boldly drawn on in defence of the theory under consideration. With a hyper-scientific caution, its advocates refuse to take into account any thing (incompatible with their theory)any one species of animal that has not been proved by a very overwhelmingly large number of very accurate observations. And