The above quote is a slightly modified version of “Segal’s Law”:

A man with a watch knows what time it is. A man with two watches is never sure.

The quote itself traces back to the The San Diego Union newspaper, initially publishing the quote as a humorous joke. From there, it bounces around through various newspapers, and in 1961ngets falsely attributed to KIXL radio broadcaster Lee Segall. It continues to bounce around, ultimately becoming Segal’s law.

While wandering through history as a joke, the underlying axiom is a very powerful statement for data analysis and sources of truth.

There’s a related saying from the old days of sailing: “When setting to sea, bring one chronometer, or three.”

When you have a single point of information, that’s all you have and there’s nothing else for comparison. Whatever errors and inaccuracies exist in that data, known or unknown, are taken into account and decisions get made.

When you add a second source of information, a paradox occurs when they don’t say the same thing. Which one is right? Is it the first, the second, or neither? It becomes very easy to get paralyzed figuring out whether your information is right or wrong, and no decisions get made.

With 3 pieces of information (or more), you can deduce or infer any inaccuracies or inconsistencies, and ultimately get back to decision-making instead of analyzing data accuracy.

We all have multiple clocks around our homes, computers, phones, and watches. Are we ever really sure of the time anyway?