I asked this in another thread but I may have been off topic.. I'm not quite sure which thread to ask in.. I was wondering if it is okay to say that you can measure an inch in any direction but you can only measure time in one direction. And if, in the same vein, is it okay to say that you can measure an inch from the same point repeatedly but that once you measure time from a point you can't return to that point to remeasure it ever again? I was wondering if the above is possibly wrong? I'm just curious what the position is on this?