Let's begin this op-ed with a brief warm-up exercise. Will all of you who thought "Islamist terror" after the bomb attack on the Dortmund team bus please raise your hands?

Mine is up, and I'd bet yours is too. It all seemed to fit so well. Supporters of IS terrorist networks had already targeted a football stadium in the Paris attacks in November 2015, in which 130 people were killed. The logical extension was to target a football team. What a perfect soft target. And if we've learned anything in the new millennium, it's that Islamists are fiendishly good at finding soft targets.

Except that's not what happened. If authorities are correct, the villain in the Dortmund bus bombing story was inspired not by religious fanaticism but by greed. I think it's safe to say that no one saw that twist in the plot coming, even though greed is an archetypical reason why human beings commit evil deeds.

The stories we tell

It's no accident that I've slipped into the vocabulary of literature in talking about popular reactions to the bus bombing. As the critic Peter Brooks argued in his book Reading for the Plot, human beings understand the world and their place in it by putting together coherent stories about it, "recounting and reassessing the meaning of…past actions and anticipating the outcome of…future projects."

Conventional stories literally "make sense." They not only reconstruct past events - they construct the meaning of those events. Odysseus eventually finds his way home, Faust wins his wager with Mephistopheles, and Rosebud turns out to be Citizen Kane's sled. No one would be happy with a Sherlock Holmes story that ends with the famous detective saying, "Frankly, my dear Watson, I have no idea whodunnit."

Terrorist attacks confront us with chaos, and chaos makes us feel uncomfortable. So with every terrorist attack, we immediately try to relieve our unease by finding a coherent storyline. Who could have done this? And why? The problem is that in our zeal to find explanatory narratives, we often rush for the story that's most convenient. The suspect in the Dortmund bus bombing, Sergej W., seems to have tried to exploit this reflexive tendency, by sending the police letters from purported IS followers claiming responsibility for the attack.

Resisting easy explanations

The obvious lesson in this story is that in cases of what seem to be terrorist attacks, we all need to be doubly on our guard against jumping to conclusions. That's not to deny that there is a connection between radical Islamism and acts of terrorism. Insofar as terrorist acts are a central part of the Islamist strategy, there is a strong connection. But Islamists aren't the only ones who use terrorism, and the emotional force of a terrorist attack makes people particularly susceptible to manipulation - and mistakes.

The fact that the Dortmund bus bombing subject was apprehended at roughly the same time as a gunman launched what seems to be a genuinely Islamist attack on police officers in Paris only underscores the need to focus on facts and to differentiate when we try to understand and combat terrorism. Reality is often more complicated, and sometimes just different, than it initially appears.

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