Appropriate saying for thermostats as well

[Bluewater]

A man with one watch knows what time it is. A man with two watches isn't sure.

 

[sourland]

A man with one watch knows what time it is. A man with two watches isn't sure.

He is if both indicate the same time.

 

[Bluewater]

This is an old Oriental quotation; the man with one watch must accept the time indicated; but the man with two (if different), has a more complex decision to make. (Of course, the two watches will respectively be exactly correct two times a day; but you won't know when that occurs without the correct input from an accurate timepiece). The guy with two watches showing the same time is going to be reassured that he's nailed it. But maybe not. (I have lots of clocks in my home; but last week they were all an hour off!).