I came across this on the web and if it hasn't been discussed b4, quite interesting.

Time only exists where change exists.  It is the measurement of interval between events.  Some say it is the measurement of entropy.  All things were set in motion by the Big Bang, so the clock started ticking then.

But if a watch ticks and no one sees it, is there still time?

space-treker : It depends on how you percieve the dimension of time. If for example you wish to think of time as present time, then it will require events to fill that requirement, if you wish to think of future time, it will require the knowledge of events that with some probabiliy will take place, however if you want to think of time the dimension,  think of " NOW ", now being, the necessary element for past, present, and future, to myself this is the dimension of time without extras. Time past the point of NOW is the past, time with now and acknologing the events in the past, and expecting events to occur, is the present. Dissipation of electromagnetic energy is an event in past, now, and future time. Just think about it.