Our New Relationship to Mechanical Force

In their book “The Second Machine Age”, Andrew McAfee and Erik Brynjolfsson claim that the Industrial Revolution brought on perhaps the biggest technological shift in the history of human existence. As the story goes, James Watt perfected the steam engine to give rise to steam trains, mills, factories and a host of new products. But the simpler, more salient shift was from the animal to the machine. For the first time ever, mechanical work could be done by entities that were not biological - energy could be created from something other than human or animal muscle. Prior to this revolution, strength existed on a fairly narrow spectrum – humans had varying levels of strength but most humans were weaker than most bulls; animal strength could be augmented by systems of pulleys and gears but always by some finite, imaginable multiplier.

Now though, we have a very different relationship to mass. Now, pulling a single lever (maybe 10N of force) on a crane, for example, can be used to lift hundreds of kilograms. The multiplication factor is basically infinite. Since the energy is being created somewhere else, even the smallest trigger can set off huge motion.

It used to be that knowing how heavy something is, was equivalent to knowing how much effort would be required to move it. A boulder is more difficult to move than a pebble. And the metaphor seems to extend beyond the physical into the linguistic. The death of a family member is heavy because the weight of their absence will linger for a long time - it will take great strength, patience and maturity shift the grief. The amount of effort required to work through a difficult decision is proxy for the difficulty of the decision itself – it used to be that there was an intimate relationship between the amount of human effort involved, and the size of the thing in the real world.

To illustrate, a grown male lion weighs about 200 kg. Three male lions would be about 600kg. It is difficult to appreciate exactly what that means unless you’re ever tried to lift 600kg, or even better, if you’ve ever had to wrestle someone who weighs 120kg. Suffice to say, if you went head to head with a group of lions, you would lose long before the fangs and claws came into play. In a contest of mass vs mass, the thing with more mass always wins — at least that’s how it used to be.

Moving 600 kg requires huge strength, ingenuity, or just sheer manpower. Raising a 600 kg block of concrete would have, long ago, taken several men plus all the pulleys and contraptions they could muster. This was a time when, with each pull of a rope, the men could feel the weight of what they were moving.

However, contrast this to the moving things we encounter in modern day-to-day life. A typical family car weighs about 2,000 kilograms – really a monumental mass by human standards — but moving the car requires simply clicking into gear, and pushing a pedal. In fact, we can move this mass at phenomenal, superhuman speeds by pushing harder on exactly the same pedal. A Boeing 747’s maximum takeoff weight is (according to a quick Google search) 439,985 kilograms and a train when loaded can weigh upwards of 10,000,000 kilograms. And yet, moving these objects today requires about the same amount of force as pushing a car pedal. Which is to say, in the modern day, the relationship between the mass of the object and the amount of human effort needed to move it is completely broken. We forget, while sitting in trains and flying in planes, just how badly these objects would destroy us if we challenged them.

The other consequence of this relationship is that hefty objects, cars and trains are like rubber bricks. The weight they seem to have based on their size and appearance doesn’t translate into the force required to move them. I wonder if this makes us feel, deep down, that the world around us is somewhat artificial – that we have upset thousands of years of neural networking by giving humans such power over physical objects. Or maybe this worry is silly, and the human brain has easily adapted to this world we are living in. Maybe the tool of burning oil for energy is no different than the tool that is fire, or the tool that is the knife. All I know is that several times over the course of my travels last year, I would see train rolling into the station and think - “Wow, that thing is really very heavy!” Any sufficiently advanced technology is indistinguishable from magic.

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