Murphy's law is not a joke !

When I was younger I always thought Murphy's law was a kind of a joke. It sounds so fatalist. Intuitively I believed there was some truth in it, but I couldn't point it out. Here is its most popular, concise and general formulation.

              "Everything that can go wrong will go wrong"

I recently (re)discovered its mathematical justification and thought it might be usefull to present here. Hold your socks, here it goes.

Let p be the probability that the "wrong thing" happens in one event. The probability that it doesn't happen is then 1-p. The probability that it never happens in n events is then (1-p)^n. Since 1-p is smaller than 1, this probability tends toward 0 when n gets big.

So the correct and complete law formulation should be
 
    "Any possible outcome will happen at least once for sure, provided that it is given enough opportunities to occur".

So Murphy's law is not complete and general enough on two aspects:

  - it applies for good events as well as bad events;

  - it depends on the number of opportunities to occur.

Ok, my formulation is less fun than murphy's law and it is probably because of its provocative formulation and partial correctness that it attracts so much attention. But just to be sure you didn't miss the point, when you consider the probability of occurence of something, good or bad, take in account the number of opportunities it has to occur.

That's true for startup success as well as for car or software crashes or anything else. People often focus only on  p and forget about n. The YCombinator funding model is based on making n increments cheap. And this is as good for entrepreneurs as for investors.