What can we say of space and time when we consider them as attributes of nature and as attributes of nature in the context of experience? The following is an examination of this question in the light of those portions of the writings of Locke and Kant which were concerned with it. Since men have no difficulty in speaking about and utilizing the familiar spatial and temporal relations of things, we begin with these and shall avoid definition and debate except insofar as it is pertinent to the present inquiry. Nor shall we consider it necessary to examine space and time in any other context as, for example, that of modern physics. The familiar world is the necessary condition for the conception of any intellectual development of it, and to begin with the intellectual development is to render it unintelligible. This is evidenced in several ways. When we begin with physics and mathematics, we cannot account for the world within which we live and consequently end in scepticism about it, whereas this is not the case when we begin with the actual world itself. Furthermore, the manifestly perceptible is indispensible to scientific enquiry for we must employ instruments and objects directly accessible to experience. Without these there would be neither experiment, observation nor inference. Communication would be impossible without it as well as discussion about subject matters such as logic and esthetics. It is for these reasons, therefore, that we begin with the familiar spatial and temporal relations of things.