You look at a clock and it tells you it's eight o'clock, you know the number of hours that has been before eight; you know the number of hours you've got after eight. You can now measure your time to see if you can get done a number of things you've got to get done. History serves the same purpose.
![You look at a clock and it tells you it's eight o'clock, you know the number of hours that has been before eight; you know the number of hours you've got after eight. You can now measure your time to see if you can get](http://cdn.quoteddaily.com/images/john-henrik-clarke/you-look-at-a-clock-and-it-tells-you-its-eight-oclock-you-know-the-number-of-hours-that-has.jpg)