How did the guy who invented the first clock know what

[Floyd R. Turbo]

time it was?

[underpants]

1. They set it at midnight when gas stations have to stop selling beer

[democratisphere]

2. Sundial.

[DetlefK]

3. At midnight, the darkness is at its highest point up in the sky.

[ProudLib72]

4. They found a country with trains that run on time and set the new clock to that schedule

[jberryhill]

5. They looked at their cell phones, duh

[murielm99]

6. You sound like my kid when he was about four years old.

That is not necessarily a bad thing.

[malthaussen]

7. He called the telephone company for a time check. n/t

[Boxerfan]

8. Stellar observation was a thing back then

And the concept of time in a accurate form was possible but it took a telescope & keen observations-and math.

The Elgin watch factory had its own observatory for time keeping to the nth degree.
https://en.wikipedia.org/wiki/Elgin_National_Watch_Company_Observatory

[jmowreader]

9. Noon was when the sun was directly overhead

[DFW]

10. Just turned on his cell phone

Then copied and pasted onto the dial.

[Major Nikon]

11. Calibrated to when he had to pee in the morning