The proposition that oscillations of a pendulum measure nothing, but count simultaneities apparently means that oscillations, as physical facts, have no duration of their own, and so cannot overlie duration as a unit of measurement. This would at least be an intelligible, even if a false, representation; but, if oscillations cannot measure, how can they count? What is just that difference between counting and measuring, by virtue of which that which can count cannot measure? Simultaneity Bergson defines as the intersection of space and time. Now, counting, as well as measuring, implies a continuum. Measuring, certainly, if it is theoretically perfect, can apply only to a continuum; but counting, which obviously presupposes discreteness, then requires also the indispensable condition and correlative of discreteness, which is continuity. The intersection of space and time thus evidently involves equal continuity and discreteness in both; if they can intersect, and their intersections are countable, each is both countable and measurable. The “purely” temporal phenomena of our conscious life, although interpenetrating, “correspond individually” to an oscillation of the pendulum, which, though a “purely” spatial phenomenon, “occurs at the same time with” the former. Such “endosmotic commerce” between psychical and physical events seems to be decisive for a real community of nature between their respective forms, time and space--such, for instance, as common homogeneity and continuity. CHAPTER II MIND AND MATTER, SPIRIT AND BODY