Does Anybody Really Know What Time It Is?

     The United States (most of it) just went through the Spring ritual of changing to Daylight Savings Time. Or, as a cartoon published during my childhood indicated, cutting off one end of the blanket and sewing it on the other end. Along with the changing to DST comes the biannual articles and discussions on whether we should stay with Daylight Savings Time (I assume that it would then become the new "Standard" time and the old "Standard" time would disappear) year round.
     Personally, I don't know the "best" answer. But it does call out vividly that time, as displayed on a clock, is arbitrary. What we call time is a human invention. Of course, time as a reflection of entropy (physical movement towards disorder) exists without humans -- but it is unknown whether the manner in which we perceive time (past -> present -> future) is fixed or a matter of perspective.
     Within the general human situation, perception of time is generally more important than the numbers with which we associate it. It takes "forever" to receive an anticipated message or event. Children grow up "so quickly". In my experience (I cannot say about yours), looking back at time seems much shorter than looking ahead.
     I have a personal theory that perceived length of time is proportional to one's chronological age. Thus, for a five-year-old, a year is an enormous amount of time because it is 1/5 of their life so far. But, for a 60-year-old, a year seems much shorter.
     Perception of time is also cultural. Some cultures (stereotypical for the Swiss citizen) are "ruled by the clock" -- everything must be done exactly "on time" and the schedule rules. Other cultures (it is supposed to be traditionally true for many in the First Nations) see it as a general framework. Thus, "tomorrow morning" may vary plus or minus a day. And yet other cultures make an assumption of inherent delays in most planned events -- so a plane that takes off at "7pm" might actually take off sometime between 6:30pm and 9pm (or later, if mechanical or staffing problems intercede). And that is OK because punctuality is not expected.
     Another variable of perceived time is focus. If I am focused on doing something -- because of a deadline or because I really love doing it -- then I am concentrating on the task and not on the time and time will go "fast". If I am thinking of things other than the current task, "waiting" for something "better", or trying to keep in mind multiple things that should happen within the same period, time goes "slowly".
     One more parameter to the perception of time is emotion. If you are dreading something, time usually seems to go faster. If you are looking forward to something, then it "just never arrives". Perception of time seems to be the inverse of how much you want the event to arrive. I don't want it, it happens "faster". I do want it, it happens "slower".
     So, to answer the original question -- no, probably no one really knows what time it is. Does anyone really care?