“Slack”: The key to resilience in a world that keeps breaking

I’m going to tell you how to stay resilient in a world that keeps breaking. But first, I need to tell you about my brain.

In 2023, I had surgery to remove part of my cerebellum. That’s the region of the brain responsible for balance, coordination, and thousands of other functions. Though it makes up just 10% of brain volume, the cerebellum holds about 80% of the brain’s neurons. Not exactly optional software. If you told me before the operation that I’d walk normally again, I might’ve laughed. Or cried. But something extraordinary happened in the months after surgery: I started to heal. 

I learned to move again. I adapted. What I discovered — and what neuroscience confirms — is that the brain has a remarkable capacity to reroute and rewire. It carries redundancy in its circuits. It doesn’t always rely on the same neural pathways. It has “slack” built in. And that slack saved me.

Here’s my point, which will resonate no matter what field you’re in: we don’t talk enough about slack. We worship efficiency. We optimize. We squeeze. But when the storm hits — and it always does — what keeps you afloat isn’t optimization. It’s excess capacity. Wiggle room. Optionality. Margin for error. It’s slack.

Slack is why some businesses survive chaos — and others don’t

In 1997, a fire broke out at an Aisin Seiki Co. plant in Japan. That might sound like a minor event — until you realize Aisin was the sole supplier of a small but essential brake valve used across Toyota’s entire vehicle line. Toyota was on the brink. Just-in-time manufacturing meant they had virtually no inventory. They were days away from shutting down global production.

But then something remarkable happened.

Within hours, a swarm of other suppliers — many of whom had never made the part before — stepped in. They repurposed tools. Re-engineered molds. Delivered parts in record time. Toyota’s survival wasn’t a stroke of luck. It was the result of years of cultivating deep supplier relationships. Of decentralizing know-how. Of embedding flexibility and trust into the entire system. It demonstrated the value of the Japanese keiretsu system, in which businesses maintain interlocking relationships that provide mutual support during times of crisis.

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They had slack — not in warehouses, but in people, networks, trust. When everything broke, that slack became their lifeline.

Nature figured this out a long time ago. In fact, slack isn’t a business concept. It’s a biological principle. Let’s start with plants. In fire-prone ecosystems, many trees store dormant buds beneath their bark. These buds don’t contribute to everyday growth. They’re not visible. They seem, frankly, unnecessary. Until they’re not.

When fire scorches the canopy and destroys surface branches, those hidden buds activate. They sprout new growth. They bring the tree back to life. That’s slack. It’s backup potential. It’s not efficient in the short term — but it’s what makes long-term survival possible.

Other plants take a different route: redundancy in reproduction. Dandelions, for instance, release hundreds of seeds for every one that might take root. It looks wasteful. But in unpredictable environments, it’s the smartest play. Some seeds won’t make it. Most won’t. But a few will land in the right soil, at the right time, and ensure the species survives. This is the biological version of optionality. You don’t know which bet will pay off. So you make many. You leave room for adaptation. Slack is how nature says: “I don’t know what’s coming. But I’ll be ready.”

Animals carry slack, too — inside and out. Your immune system, for example, maintains an army of idle B and T cells trained to recognize threats you’ve never encountered. These cells consume energy. They sit in wait. They look inefficient. But when a virus invades, they become the frontline. Your lungs are the same. At rest, you’re using only a fraction of their capacity. But if you sprint, climb, or fight for your life, your lungs can rapidly scale up. That surplus — that dormant function — is what lets you survive sudden change.

Even octopuses have slack. Two-thirds of their neurons live in their arms, not their brains. If their central nervous system is disrupted, each arm can still move, explore, even make basic decisions. Distributed intelligence means no single point of failure.

All of this costs energy. It defies optimization. But it’s what makes these creatures resilient. Nature does not optimize for efficiency. Nature optimizes for durability.

There’s a famous quote by Nassim Taleb that goes: “The opposite of fragile is not robust. It’s antifragile — a system that gains from disorder.” That’s what slack enables. It’s not just surviving shocks — it’s benefiting from them. Evolving. Growing stronger. Gaining new capabilities. But you can’t do that if you’ve squeezed every ounce of margin out of the system. You need to leave space. You need to hold something in reserve. Slack is the precondition for antifragility.

So what happens when systems lose their slack?

We’ve seen it — again and again. Hospitals, optimized for normal capacity, collapse under the weight of a pandemic. Supply chains, built for just-in-time perfection, crack under global disruption. Startups that spend every dollar chasing growth find themselves with no financial cushion when markets turn. The systems were “efficient.” But they weren’t resilient. No margin = no resilience.

Slack doesn’t always look like strength. Until it is. Slack can look like waste. A company sitting on too much cash. A schedule with too much white space. A team that’s cross-trained beyond immediate necessity. But slack is strength in disguise. When pressure builds, it’s your buffer. Your option set. Your room to move.

In 2008, when the financial crisis wrecked Wall Street, Berkshire Hathaway wasn’t the most innovative firm. But it had slack — in cash reserves, in diversified businesses, in long-term relationships. So while others panicked, Buffett made deals. Slack became advantage.

In 2020, when COVID shut down travel, Toyota once again weathered the storm better than most, in part because of the lessons learned in 1997. They had diversified suppliers. Built redundancy. Protected key relationships. 

Slack is a quiet kind of power. It doesn’t show up in quarterly metrics. But it shows up when everything else breaks.

So how do you build slack into your life?

You stop trying to optimize every moment. Every dollar. Every effort.
You build in space — for rest, for reflection, for recovery.
You keep some money in the bank — not for ROI, but for resilience.
You cross-train your team.
You cultivate relationships before you “need” them.
You learn to hold back a little, even when things are going well.
You build a system that bends, not breaks.
You think like a brain. Like a tree. You learn to love slack.

Because the world will keep breaking. And when it does, it won’t be the leanest or most optimized who survive. It’ll be the ones with margin. The ones with optionality. The ones with slack.