C.D. Broad begins his essay warning us about analogous arguments of time and space. Although it may seem that the single dimension of time, compared to the multiple dimensions of space, gives way toward simplistic reasoning, they are very complex and difficult matters. In the deceiving analogy,
``we treat our geometry in terms of unextended points and their relations, [in the same manner as] we treat out chronometry in terms of moments without duration and their relations ... just as we never perceive points or even unextended particles, so we are never aware of moments or of momentary events.''[1]This seems a convincing argument in order to dismiss time as a simple problem solved. Broad, however, notes two peculiarities with Time: its characteristic of the intrinsic order and intrinsic sense.
Three points, claims Broad, on a straight line have an intrinsic order. This means that on a line with three points (A, B, C,) A is between C and B, or B is between A and C. Whichever way you would like to see it, this order is independent of anything crossing the line. By intrinsic sense, Broad means that there is a distinct difference between ABC, and CBA. The intrinsic sense is assigned to the points by the relative position of the right-ness and left-ness of the line from the observer. If, however, we were to place this spacial analogy in respect to time, then Broad claims that we would need a ray. This ray would give the line an intrinsic sense. In this way, you know that you are travelling in a particular direction, safely saying that the intrinsic sense of the line is indeed ABC (or CBA, &c.) So now the argument has fallen back on itself in a circular manner: we are attempting to explain (and hopefully simplify) time; yet we are using the concept of time (before-ness and after-ness) by making the straight line a ray.