Hanlon's razor: it was more stupidity than malice
Kapitoly: Occam's Razor, Hanlon's Razor
Hanlon's Razor tells us not to assume the worst of others. Hanlon's razor is most often described by the aphorism
Don't look for malice where stupidity is a sufficient explanation.
We humans often tend to see the world in the worst colors and expect only the worst from other people. The waiter at the restaurant spilled beer on us? I'm sure he did that on purpose because we forgot to say hello. The boss didn't approve our vacation? I'm sure she's just getting back at us for the poor quarterly results. Mars Climate Orbiter burned up in the Martian atmosphere? Someone must have sabotaged NASA's scientific work!
It's easy to see the malicious intent in these cases because it gives us a clear-cut explanation for what happened. The waiter who has been working in that restaurant for five years isn't stupid enough to throw beer on us, there must be some malicious intent! In fact, it's far more likely that he slipped on the water spilled by the kid at the next table and accidentally spilled the beer. The elderly boss isn't exactly computer friendly and can't set up notifications. She doesn't even know about the vacation we asked for in the system. And the Climate Orbiter? It really did burn up in the Martian atmosphere in 1999 because two companies disagreed on whether to use the metric (i.e. meters, kilograms, etc.) or imperial (i.e. feet, pounds, etc.) system. In the end, each company accidentally used something else, and this led to the disaster.
Are you the bad guys?
Can you imagine yourself: how many times has it happened that you have hurt someone on purpose, that you had malicious intent? And how many times have you simply forgotten something? You didn't notice something? Unless you are a psychopath, mistakes are much more likely to be made out of inattention, carelessness or stupidity than out of malice.
Similarly, one can look at various conspiracy theories. We may think that the government, politicians and everyone around us is trying to deceive us, that they are all acting to enslave us. The moment we say to ourselves after all, they aren't stupid enough to do XYZ, let's remember Hanlon's Razor: it's much more likely that they really are that stupid.
Is there really no evil in the world?
Of course there is evil in the world. Hanlon's Razor is just telling us that evil intent shouldn't be our first thought when we run into a problem. Usually, someone's incompetence or mistake is a more likely explanation than someone's evil intent. But sometimes it does happen that someone's malice is the root cause. The world is not a perfect place to live.