The most dangerous person I ever met was a retired Mossad killer.

I know, I know, I spent a decade giving my American friends crap for assuming every Israeli knows a Mossad killer, and here I am telling you about literally knowing one. In my defense, I don’t actually know him. We merely spent a long weekend together on a bike trip through the Israeli desert, together with a friend of mine who used to go by the name Guttman the Gray and another guy called Shayke who went on to become a Zen master in Northern Israel.

Yep, we were huge dorks, but we didn’t care.

Danny, the retired guy, was an unimposing, short man in his 60s, with a belly, long and wispy silver hair, and a lisp. He made his own energy bars. He was a recluse. What I’m trying to say is he made George Smiley, John le Carré’s fictional anti-hero spy, seem like an upstanding member of society and a raging extrovert. However, since we were all obsessed with martial arts at the time (and for almost a decade afterwards), he was willing to offer some of his knowledge. And his knowledge came down to this: it’s not the size of the dog in the fight, it’s the size of the fight in the dog.

It sounds stupid. I knew it was stupid: there was a reason MMA had weight classes and if I tried to sweep a guy 40 kilos heavier I’d get a sprain (I tried, and I did). Small guys don’t win in straight up fights. This oddball “Mossad guy” wasn’t going to tell 23 year old me what winning a fight was all about. I had teachers. I was informed.

And then, to make his point, Danny took my friend down, mid conversation, out of nowhere, with a shoelace. No, I have no idea how he had a shoelace in his hand all of a sudden and frankly I couldn’t retrace his actions to save my life. I do know this: one moment the guy, a head taller and probably 50 kilos heavier than Danny, was standing. The other moment he was down and was not a happy camper. For us, fighting was wearing our nice training gear and bowing to each other and then engaging in some gentlemanly exchange of blows. For Danny, every second was a chance to kill you when you weren’t looking.

This was my first visceral “oh shit” moment. I had an immediate epiphany that maybe I had no idea what I was talking about, and that with enough constraints removed there are many ways to reach a goal. Quite literally, there are many ways to kill a guy. The weekend continued with a more mellow tone. Suddenly we didn’t feel like we had a lot to contribute to the discussion.

I think about that episode often when facing adversity. I learned, years later, about equifinality: the principle that in open systems a result can be reached through multiple paths. I’ve always disliked riddles, most board games, and generally situations that force you to accept arbitrary limitations set by others. Conversely, I’ve learned this is one of the main reasons I enjoy startups. There are many ways to solve complex-enough problems.

Remembering equifinality is a good way to develop an antifragile mindset. It helps me process advice about dealing with covid-19 and generally any chaotic situation. No one really knows, and there are many ways out of this, and like one retired guy who may or may not have been a real killer, once I accept there are very few constraints, I can reach incredibly creative solutions.