In preferring the Design Hypothesis over the Random Hypothesis, we prefer the explanation that strains our credibility less. >>> The Surprise Principle

Actually, the story of finding a watch and asking about the reason for its complexity and how it came to be there goes back to William Paley (1743 - 1805). It is an interesting version of the classic Design Argument for the existence of God.

Making Observations

Now, back to our watch on the beach. Let’s say you have made some kind of extreme time-lapse recordings or observations (O) that track the watch throughout its development:

   You see that the watch was produced by the random actions of nature: wind, rain, flooding, sunshine, etc. The Random Hypothesis (H₁)

   You see a watchmaker construct the watch. The Design Hypothesis (H₂)

Your observations O would be unsurprising if H₂ were true; but O would be very surprising if H₁ were true. And according to the Surprise Principle, you should favor the hypothesis with the unsurprising observations.

H₁: O is quite improbable.

H₂: O is quite probable. 

Moreover, considering the features of the watch, we can also infer that the watchmaker must be intelligent—at least on the order of human intelligence.