Yet, historically and practically the notion of 'time' has always been tied to a clock - the daily cycle, the change of seasons, etc. For example, when people s

Yet, historically and practically the notion of 'time' has always been tied to a clock - the daily cycle, the change of seasons, etc. For example, when people said, "time has passed," they meant a certain number of natural cycles - days, seasons or years. The abstract, "theoretical" time, untied to any clock, is a relatively recent invention and, in fact, very well may be a fiction.