Another very important point is that cognitive relatedness is effective. By this I mean that just as, when the earth is in gravitative relation to the sun and the other planets (the constitution of nature being what it is), changes take place because the parts of the system as a whole are in this field of effective relatedness; so too, when the organism is in cognitive relation to its environment, changes in this system also take place just because a part of the whole system is in cognitive relatedness to the rest of the system. That means that the cognitive relation really counts--that it is not merely an epiphenomenal accompaniment of changes which would be precisely the same if it were absent. The 'sum of energy' presumably remains constant. There is no necessary interference with physical principles. But we know of so many cases in which the direction of change may be changed without any alteration of the 'amount of energy', as the phrase goes, that I see no reason, based on physical science,[80] for denying this kind of effectiveness, within a field of cognitive relatedness, if the facts seem indubitably to point to its existence. To assert that the presence or absence of cognitive relatedness makes absolutely no difference appears to me, I confess, little short of preposterous; to urge that it may be brought under the rubric of physico-chemical relatedness surely involves the ignoring of differentiating features, which science should not ignore. But, on the other hand, to invoke an immaterial psychic entity[81]--unless this merely names the relatedness itself[82] as gravitation names the gravitative relatedness--appears to me quite unwarranted in the scientific universe of discourse.[83] I must, however, draw to a conclusion. I cannot but think that Spencer failed to bring cognition and the conscious awareness it involves into really close touch with the rest of his philosophy of science. No such double-aspect theory as he accepted affords a satisfactory avenue of scientific approach. But where Spencer failed, who has come within measurable sight of success? We are only just beginning to see our way to stating the problem in such a form as to bring it within the purview of science. What we must insist on, as followers, at a distance, of Herbert Spencer, is the treatment of this type of relatedness on lines similar to our treatment of other types of relatedness within one order of nature. Surveying his work as a whole, we may confidently assert that Spencer brought to a conclusion a great task, and was himself great in its execution. The present generation can, perhaps, hardly realize how potent his influence was on the thought of the latter half of the last century. Many of his conclusions ran counter to those which were, in his day, widely accepted. If only they seemed to him to be true, however, he held to them with a tenacity which his opponents branded as obstinacy. But as he himself said: