— 187 —
A good measure of Time must divide its whole Duration into equal periods.       §18. In the measuring of Extension, there is nothing more re-
quired, but the Application of the Standard or Measure we make
use of, to the thing of whose Extension we would be informed. But
in the measuring of Duration, this cannot be done, because no two
different parts of Succession can be put together to measure one
another: And nothing being a measure of Duration, but Duration; as
nothing is of Extension, but Extension, we cannot keep by us any
standing unvarying measure of Duration, which consists in a
constant fleeting Succession, as we can of certain lengths of Ex-
tension, as Inches, Feet, Yards, etc. marked out in permanent parcels
of Matter. Nothing then could serve well for a convenient measure
of Time, but what has divided the whole length of its Duration into
apparently equal Portions, by constantly repeated Periods. What
Portions of Duration are not distinguished, or considered as dis-
tinguished and measured by such Periods, come not so properly
under the Notion of Time, as appears by such Phrases as these, viz.
before all time, and when time shall be no more.
Locke Hum II, 14, §18, p. 187