When you hear hoofbeats, think of horses, not zebras

The other night I attended a meeting in which a key participant avoided answering an important question. I passed a note to a friend, saying, “If it ducks like a duck, it’s a duck.” To which he replied with an equally zoological note, “When I hear hoofbeats, I think of zebras.”

I wasn’t familiar with this line, but it had the ring of a popular saying, so I tried to deduce what he meant.

My first thought was of Monty Python, of course, and the scene with the coconut-shells being rapped together to sound like hoofbeats… but I couldn’t see any relevance.

Then I thought it might have to do with the classic zebra question – is the zebra marked with white stripes on a black background, or black stripes on a white background? But that really had no relevance here, that I could see.

So then I thought about zebras and how life isn’t black-and-white. Perhaps I should hear hoofbeats and think of horses, understanding that life can be gray sometimes, rather than draw black-and-white conclusions a la zebras. Was this a rebuke about my swift judgment of the duck?

I was confused… so, upon arriving back at shul after the meeting, I turned to Wikipedia, and found out that it’s actually a medical aphorism, related to diagnosis. Horses are simple, Zebras are complex. Essentially, the message is this: When faced with symptoms, assume the least-complex diagnosis first. (There’s even a book with that title, available at Amazon here.)

(Which, by the way, means that when I took a labyrinthine route to reason out the meaning of those words, I actually ended up violating their advice...)

To put this in other words, the line is another version of Occam’s Razor, or the KISS principle (Keep It Simple, Stupid): Don’t reason beyond the data.

Which, while good advice, is easier said than done. Human beings are physically and spiritually wired to reason beyond the data, to make leaps of deduction that have little relationship with reality. When we are happy about this, we call it intuition and human creativity; when we are less pleased, generally after the fact, we call it foolishness.

It reminds me of an article I read a month ago, regarding an experiment with dog owners who were told that their dog had done something wrong. A great percentage of them thought their dog was wearing a guilty expression in regret for its crime – but, in fact, in half of the cases the dog had done nothing wrong at all. If anything, the dog’s expression was a response to rebuke, not a response to an emotion of guilt, but the dog owners had assumed that the dogs could feel guilt for their misdeeds.

We see zebras all the time in the realm of religion. It’s the tendency that encourages people to see their deity in a piece of toast, or a fluffy cloud, or the trunk of a tree. It’s the tendency that allows people to see patterns in their lives, in events both positive and negative. It is not always a pro-religion force, though; we also see zebras when we question Gd’s existence, finding proof of randomness or malice wherever we choose.

And, as so often happens, the gemara’s sages described this tendency perfectly. They said regarding Bilam (Makkot 10b), “בדרך שאדם רוצה לילך בה מוליכים אותו,” which translates roughly as, “A person will be brought along the path he wishes to follow.” It was true for Bilam, and it’s true for us as well.