On Time and Memory and Dreams
Our space is called three-dimensional because it takes three numbers - measurement in three mutually perpendicular directions - to determine and mark out any particular point from the totality of points. Time, as the individual experiences it, is called one-dimensional for an analogous reason: one number is all that is required to determine and mark out any particular event of a series from all the rest. Now in order to establish a position in a space of four dimensions it would be necessary to measure in four mutually perpendicular directions. Time curvature opens up the possibility of a corresponding higher development in time: one whereby time would be more fittingly symbolized by a place than by a linear figure. Indeed, the familiar mystery of memory calls for such a conception. Memory is a carrying forward of the past into the present, and the fact that we can recall a past event without mentally rehearsing all the intermediate happenings in inverse order, shows that in the time aspect of memory, there is simultaneity as well as sequence - time, if we choose to figure it as one-dimensional, ceases to be linear and becomes plane. More remarkable illustrations of the sublimation of the time-sense are to be found in the phenomena of sleep and dreams.