A Silly Question

He went out to the garden clock to check the time on the Sun Dial sir.
And just to add, women live to do that to us, unfortunately for them they haven't won yet.

The source for all time on earth is the "star time" which is determined with the help of a special telecope, a so called "transit instrument" in an observatory.

Time is elastic. The time zones were established by the railroads to accommodate their schedules.

I am a traditionalist, I use sticks and bones to track the phases of the moon and the seasons.

there are other ways of course.

At first reading of this, I just "harumphed" and muttered "sextant" ( stvalentine 's answer is more correct and sophisticated). Then I reminded myself that I find as I age that I know less and less about more and more.

Your wife's question isn't the slightest bit silly; it could actually, and has for some, been a part of a life's work and/or obsession.

First define "clock". I assume we are talking about mechanical contrivances. Before the development of the minute hand, checking against a sundial would do: close enough is good enough. If the clock was off by several, or many, minutes, no harm done: vespers might be a little "late". So that's pretty easy, although it can become complex when eccentricities of orbits and irregularity of rotation are taken into account. And they were by some; I'm often brought up short by how curious and intelligent some people have been throughout history.

Travel. That's what did it. First a means of telling time was needed so ships could determine their longitude, enabling efficient and safe travel. The Scilly naval disaster of 1707 lead to the momentous development of Harrison's marine chronometer and the further understanding of lunar, star, and solar time. Then rail travel reinforced the need for accurate time-keeping: if one had train orders instructing the train to be off the main line at 1410 to clear for an oncoming train, all involved had to be using the same time and carry an accurate means of its determination; that was a lesson learned the hard way. Interestingly, when I hired on the railroad, we still had to have company-approved timepieces and carry a watch card indicating that it was being checked and serviced regularly. Not really necessary then, but old habits...

I am still trying to find out what exactly makes, say conveniently, 1200 noon 1200 noon? Surprisingly, to me, it's not the position of the sun: there are too many inaccuracies to allow for that. There does seem rather a lot of math involved. Generally, when there's heavy lifting to be done with numbers, I make myself scarce very early in the undertaking.

I'm due for a visit to the library soon. I'm hoping that given the fad for exhaustive histories of such things as salt, water, cod, pencils, amongst many other topics, there might be something along those lines about time.

So. to answer your wife's question. Originally, the clock would have been set according to some understanding of solar time. Later, an amalgamation of methods was used for greater accuracy.