When did time actually begin?
I have a secondary question: are you asking when “keeping time” began or when “dealing with time” began? Long before we had sundials or clocks, time was always part of our world. There was a time to sow crops and to harvest. Everyone recognized when days would start getting longer. Long, long ago we know when the solstices occurred. Stonehenge and other stone circles that enshrine the moment of the solstice are thousands of years old, maybe as much as nine or 10 thousand years. Which means that before those stone circles were built, we already had “time.” Just not clocks.
Time is not new and didn’t arrive with the first clock. Animals know time too. They know when it is time to mate and time to push the fledglings out of the nest. They know when seeds will ripen. They know how long eggs need to hatch.
The Duke knows when it’s time to go out and he tells us. He has it down to the minute. Even though we have a dog flap, Garry has to walk him to the door, open it to let him out, then come back down in 10 minutes to let hm back in. Mind you he goes in and out all day long, but this is Duke’s ritual. He knows to the minute when it should occur. He only gets confused when we change the clocks. He doesn’t need a clock. He has one in his head.
If you take off your watch and stop wearing it — which I did about 10 years ago — you will still know what “time” it is. It takes a few weeks to get your bearings, but you will find your way. You can tell by the light and the “feel” of the day. You can tell what the seasons are. Calendars be damned, we all know when it’s time to plant and time to reap. It may take a little practice, but you’ll figure it out even if you’ve never done it before.
It’s amazing how much we know that we don’t know we know.
We have always known, just as the birds and the deer and the squirrels know. Time isn’t just a thing we measure by mechanical means. It is the passages of life and seasons.
We have always had time. What we didn’t have were clocks. Clocks haven’t changed time, just how we measure it.