It has been the purpose of these lectures to analyse the reactions of science in forming that background of instinctive ideas which control the activities of successive generations. Such a background takes the form of a certain vague philosophy as to the last word about things, when all is said. The three centuries, which form the epoch of modern science, have revolved round the ideas of _God_, _mind_, _matter_, and also of _space_ and _time_ in their characters of expressing _simple location_ for matter. Philosophy has on the whole emphasised _mind_, and has thus been out of touch with science during the two latter centuries. But it is creeping back into its old importance owing to the rise of psychology and its alliance with physiology. Also, this rehabilitation of philosophy has been facilitated by the recent breakdown of the seventeenth century settlement of the principles of physical science. But, until that collapse, science seated itself securely upon the concepts of matter, space, time, and latterly, of energy. Also there were arbitrary laws of nature determining locomotion. They were empirically observed, but for some obscure reason were known to be universal. Anyone who in practice or theory disregarded them was denounced with unsparing vigour. This position on the part of scientists was pure bluff, if one may credit them with believing their own statements. For their current philosophy completely failed to justify the assumption that the immediate knowledge inherent in any present occasion throws any light either on its past, or its future. I have also sketched an alternative philosophy of science in which _organism_ takes the place of _matter_. For this purpose, the mind involved in the materialist theory dissolves into a function of organism. The psychological field then exhibits what an event is in itself. Our bodily event is an unusually complex type of organism and consequently includes cognition. Further, space and time, in their most concrete signification, become the locus of events. An organism is the realisation of a definite shape of value. The emergence of some actual value depends on limitation which excludes neutralising cross-lights. Thus an event is a matter of fact which by reason of its limitation is a value for itself; but by reason of its very nature it also requires the whole universe in order to be itself. Importance depends on endurance. Endurance is the retention through time of an achievement of value. What endures is identity of pattern, self-inherited. Endurance requires the favourable environment. The whole of science revolves round this question of enduring organisms.