Lindsay Winkler: We need to remove our low-pass filters

Guest post from Lindsay Winkler, musician and writer, on how society filters information. Today’s global challenges mean we may have to adjust our low-pass filters.

Electrical engineers are familiar with the concept of a low-pass filter.

Imagine you want to measure the depth of water in Sydney Harbour at different times. You could take a giant ruler, stick it in the mud, and write down the level of the water from time to time.

This series of numbers gives you a “signal”. Signals are everywhere, which makes them a really useful concept. Anywhere you can measure something over time and write down a number gives you a signal. The temperature in your house. The number of dollars in your bank account.

The problem with the ruler stuck in the mud is that there’s lots of stuff going on in the harbour, and you might not be measuring what you think you’re measuring.

What if you’re unlucky and a big wave washes past every time you’re taking a reading? You might think the water is deeper than it really is. So you could create a low-pass filter to filter out the high frequency noise (the waves) and just let through the low frequency stuff (like the tidal variations).

So you take a big clear tube, with markings like a ruler, and just have a small hole in the bottom. Top stays open, and out of the water. Now only a bit of water can flow through the hole, so anything that happens fast – like a wave – won’t appear inside the tube. You’ll just get low frequency stuff inside the tube. A low-pass filter.

Your car’s shock absorbers work exactly like this: there’s some oil inside that only has small holes that it can flow through as it expands and contracts, so that it acts as a low-pass filter for the road noise. It tries to filter out or absorb the high frequency shocks – that might occur, for example, when you hit a pothole.

Like signals, these low-pass ideas are everywhere. The reason you sweat all night during a Sydney summer is because your house is a low pass filter for temperature. The temperature goes up and down, but your house absorbs and releases heat much more slowly. So even when the night cools down outside, your house is slower to react. In this case, there’s a kind of inertial heat mass that’s slow to respond to the signal of temperature.

In fact – and now it dawns on you that I’m once again talking politics – conservatism is a similar inertial mass with respect to the signal of political ideas. And it’s a really good thing. Conservatism is the low pass filter for ideas that stops society from shaking itself to pieces with every season’s new fad. It’s like a shock absorber for the way we organise ourselves.

But even absent formal conservatism, our parliamentary system acts as a low-pass filter for change. We only have an election every three years, and it’s very rare for a government to change sooner than a couple of terms. For a whole lot of reasons, legislation coming out of a parliament changes very slowly with respect to changes in the world. And again, this is generally a good thing. We couldn’t function if our laws could change as fast as a new hashtag starts trending.

The problem arises when there’s a step change to the system. This is a high-frequency event, and parliamentary democracy is simply not set up to respond appropriately to it. In fact, I guess that’s the reason why we can declare things like a state of emergency, or martial law: it’s an acknowledgement of the fact that when things start changing rapidly, we need to take away the low-pass filter and just get shit done.

So that, friends, is my explanation of why we need to declare a climate emergency. Bet you didn’t see that coming.

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