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You Can Never Do Just One Thing

2 min

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Garrett Hardin, an ecologist, coined the "Iron Law of Ecology:"

You can never do just one thing.

Any intervention in a system changes the entire system itself.

The introduction of a new species into an environment can, for example, set off a devastating chain reaction that culminates in massive ecological damage.

Similarly, changing something as seemingly-trivial as your route to work can have a large impact on the quality of your life.

Imagine that your new route to work takes you by a McDonald's. You've been eating healthily lately, but driving by the golden arches every day reminds you of what you've been missing. On a particularly stressful day, you decide to nip in as you drive home to "reward" yourself for working so hard. Soon enough, stopping at McDonald's has become a weekly habit, a way of kicking off the weekend.

That weekly trip to McDonald's might add only 500 calories to your entire weekly caloric intake. While that might not seem like much, it could add up to an extra pound gained every two months. As your weight rises, you feel less inclined to exercise, which lowers your caloric expenditure and speeds up the entire process...

And on, and on.

It's never "just" introducing a new species.

It's never "just" changing your route to work.

The impact may be small, it may be large...

But you can never do just one thing.


There is both consolation and warning in the Iron Law of Ecology.

The consolation:

You have far more power than you realize.

Changing any part of a system will inevitably change the system as a whole. That means that when we change, the entire system changes with us.

Your actions, though they seem limited, have effects that are far-reaching and hard to understand. Your actions, no matter how small, matter in a way that will never fully be visible to you.

It is enough to act, however we can. It is enough to change, and demand change from others.

You can declare your will and watch the world transform around you. This is not hyperbole, and it is not "positive thinking." It is the truth.

You have more power than you realize.

The warning:

Be very careful what you change.

There is no way to "get out clean." There is no way of avoiding unintended consequences.

The changes we make carry costs. Intervening in a system means creating a new set of problems, obstacles, and challenges...sometimes worse than the ones we sought to remedy.

Making sweeping changes in systems we barely understand often leads to bad outcomes. We over-estimate our knowledge of how the world works and underestimate its complexity. We approach the world without the humility to ask questions, experiment, and see what works.

It's easy to open Pandora's Box. Closing it is the hard part.

Be very careful what you change.




If you can be bad, you can also be good.

Smart people love to be "morally neutral" because they think it shows how enlightened they are. I'd like to respectfully disagree.

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