NZ Lifestyle Block

POWER DOWN

Why logic rules

- Words Murray Grimwood

We can sometimes credit individual­s with superhuman powers. The people who seem to arrive at genius solutions while the rest of us are still formulatin­g the question.

It took me a long time to work out that logic was all we need. It gets us non-einsteins 90% of the way down the track for free. But thinking logically requires us to divest ourselves of instincts, assumption­s and beliefs. It’s no mean feat.

I distinctly remember the day my personal penny dropped. I was in a Bondi backyard, sweating, struggling to re-engine a Falcon ute to tow the boat we’d built. The pressure was on because we’d terminated our lease.

The old clutch had been a mechanical linkage on the driver’s side but the new one was hydraulic and on the other side. When we pushed the old top-hung pedal down we needed to physically pull the new clutcharm back towards the passenger seat.

Thoughts turned to a Bowden cable, the ones you get on push-bike brakes where a wire moves inside a tube. We found a hefty one from the hand-brake of a derelict Valiant, then used a yachting pulley bolted under the dashboard so the inner wire went from the pedal, around the pulley, back through the fire-wall, through the outer cable (the tube) and bent around under the engine.

But it wasn’t long enough to bend round and face forward so we could pull the arm back with the inner wire in the time-honored manner. Out of ideas, I made a quick call from a phone box (this was 1980) to Dad in Dunedin.

He had no idea what I was doing. It took him two seconds to solve the problem from a standing start.

“Why don’t you put the outer against the clutch-arm, and bolt the inner to the floor under the seat? They’ll still pull towards each other.” Genius. I wondered how it was he could get there so quick. He disagreed. He said he’d just turned the problem into a logical question. The mistake I’d made was in presuming that only the inner cable could do the moving, because I’d never seen anything else.

When you study what we consider to be other people’s landmark efforts of genius, you find that many of them were just hard slogs gathering empirical data.

Wilbur Wright did it with flight. He reasoned that there would be a best wingshape. He built a wind tunnel, applied spring balances and tested shape after shape. He did the same with propellers, profile after profile tested, tested, tested.

He didn’t begin by attempting to fly a motor or even a human. First it was a tethered glider, then a manned glider, then he added a motor. Empirical, logical.

Wilbur spent his final years trying to defend his invention. And losing. You can understand why he instinctiv­ely did so. If you’ve just spent the best years of your life searching for the optimal wing shape, propeller profile and all the rest, you can be forgiven for thinking you’ve produced the ultimate.

We know now that technologi­es like Wilbur’s tend to be improved upon, rapidly. Just 30 years later we would see the DC3, and 70 years later we had the stunning Concorde and 747, after which improvemen­ts became incrementa­l. Wilbur could have worked that out if he’d applied logic.

Once I’d learnt the lesson of logic, it was easy to apply it. Downhill trolley racing? Three wheels must be less resistant than four, a long trolley won’t be as twitchy to steer (and thus will waste less energy) and the driver lying prone must induce the least air resistance.

Efficient fridge? Must be top-loading (so the cold air doesn’t fall out) and placed outside the house, preferably on the south side (no need to work as hard and sometimes no need to work at all).

And so on. A life based on identifyin­g the problem and working out the simplest, least-effort way of solving it. Often, that turns out to be the cheapest too.

An added bonus. If you asked me what our society is most short of, logic would be the only item on the list. Without it, you’re just rolling dice. n

 ??  ?? A Bowden cable. Wilbur and Orville Wright’s first flight. Photo: John T Daniels, United States Library of Congress’s Prints and Photograph­s
A Bowden cable. Wilbur and Orville Wright’s first flight. Photo: John T Daniels, United States Library of Congress’s Prints and Photograph­s

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