Momentum

Momentum

Imagine a train pulling into a station and screeching to a halt. The driver doesn’t press the brakes when they want to stop. They do it well in advance, allowing enough time for the full length of the train, weighing hundreds or even thousands of tons, to come to a standstill.

A train can’t just stop moving as soon as the driver applies the brakes because of momentum. The equation for calculating momentum is p=m*v, where p is momentum, m is mass and v is velocity. When something with mass is moving, it has momentum.

The greater the mass and the greater the velocity, the greater the momentum of an object. If you’re out for a run, it takes a lot less effort for you to stop than it does for a train because you’re lighter and slower. Doubling either the speed or the mass of an object will double its momentum.

Isaac Newton’s second law of motion states that the acceleration of an object is the result of two factors: the forces acting upon it and its mass. This is in contrast to the first law of motion, which states that an object will remain at its current velocity if the forces acting on it are all balanced. Acceleration results from a net, unbalanced force; at a given net force, greater mass means less acceleration. Outside of physics, we consider something to have momentum if it is progressing in a particular direction in such a way that it would take a weighty outside force to stop it or change its direction.1

The relevance of mass has analogous application in our habits. A repeated habit can become part of our identity and routines, making it harder to change. Likewise, a widely used product can become embedded in infrastructure and business practices. Its age alone does not determine resistance; what matters is the network of dependencies and incentives supporting it. Let’s take a look at two products, lead and absinthe, and compare their social inertia.

About 2000 years ago, Marcus Vitruvius Pollio* wrote On Architecture, a wide-ranging series of books, covering not only architecture, but engineering, philosophy, and medicine. He had many suggestions and observations, one of which was, “Water ought by no means to be conducted in lead pipes if we want to have it wholesome.” Long before modern toxicology, people had raised concerns about exposure to lead.

That advice did not prevent widespread use of lead. Over the next millennia, lead was added to makeup, gasoline, and paint, and it was part of many manufacturing processes, such as printing. Concerns about its side effects kept cropping up as people kept noticing a high correlation between death and exposure to lead. Nonetheless, it was used to dilute wine, it made the pipes that carried drinking water, and it was added to face cream to help women achieve the paleness that was the social standard of beauty.

In 1910, Alice Hamilton* was appointed to head a survey on industrial illness in Illinois, USA. Over the next few years, she became America’s leading expert on industrial toxicology, providing definitive evidence of, among other things, the dangers of lead exposure in the workplace.3 Despite this evidence, the American car company General Motors proceeded with the creation of leaded fuel in the 1920s. Hamilton campaigned extensively against the introduction of leaded fuel, and she and her colleagues provided an extensive overview of the toxicology of leaded gas and the dangers of lead-tainted exhaust.4 And yet leaded fuel remained in use in the USA into the 1980s.

Paint provides another example of an established use that can persist after its risks become known. Replacing it involves changes in manufacturing, purchasing, and regulation.

The story of lead can be contrasted with that of absinthe, whose rise and fall occurred within 50 years.

“Absinthe was made from a combination of plants and aromatics, including wormwood, aniseed, fennel and wild marjoram, which were first bruised and then soaked in alcohol and distilled, creating a bitter, pear-colored liqueur. A measure would be placed in a glass, and was then diluted with ice-cold water poured through a sugar cube, turning the whole thing milky pale.”5 Starting in the 1860s, absinthe became a wildly popular aperitif—an alcoholic drink taken before dinner. “In the latter half of the nineteenth century whole districts of Paris were said to smell faintly herbal between 5 and 6 p.m., a time that became known as l’heure verte (‘the green hour’).”6

Fifty years later it was being compared to opium and being considered a major social ill. Furthermore, “in France, doctors began to suspect that it was really a poisonous drug. People were reporting hallucinations and permanent insanity.”7 Experiments were conducted, and animals sacrificed. Then, “in Switzerland, the final straw came in 1905, when a man called Jean Lanfray killed his pregnant wife and two young daughters, Rose and Blanche, after he had been drinking absinthe. The case was dubbed ‘the absinthe murders’ and the drink was outlawed completely in Switzerland three years later.”8 France followed in 1914.

Within 50 years it was used, abused, and abandoned. Interestingly, “subsequent tests have shown that much of the supposed proof of absinthe’s inherently deleterious effects were nonsense.”9 The distinction concerns risks particular to absinthe, beyond those shared with alcohol of the same strength.

So, on the one hand, we have lead, proposed as poisonous for 2000 years and we still use it, and on the other absinthe, whose suspected effects caused it to be taken off the market within 50 years. Lead, now proven toxic, is still kicking around in consumer products. Absinthe’s alleged special toxicity was challenged, yet restrictions and its reputation could persist. Why the difference? Obviously the reasons are complex, but the use of mental models is about the insight they provide. So, by using the lens of inertia, we can make some observations.

Mass matters. It is much easier to apply the force to stop a light object versus a heavy one. Lead and absinthe had different societal masses. Lead performed a number of highly useful functions in multiple manufacturing processes. Absinthe got people drunk. Lead had been integrated into many other substances, and so there is also an incentive angle. The cost of containment and remedy for lead was extremely high, and people would have had to abstain from using products they found useful, not to mention the cost of retooling manufacturing systems that relied on lead. Absinthe stood on its own. Thus, it took far less effort to remove absinthe than it is taking to remove lead.

This is part of the reason why the proof of something being harmful is not always enough to produce a change in behavior. A product, habit, or idea can become harder to displace as people build routines and dependencies around it. There are countless urban legends and popular myths that have been around for a long time and have woven themselves into our understanding of the world, despite available evidence of their inaccuracy. Sometimes it can seem monumentally frustrating when reliable information doesn’t seem to change an erroneous popular opinion. Using inertia as a lens directs us toward those dependencies: what would people have to replace, relearn, or pay for before they could change?

« For the need to think can never be stilled by allegedly definite insights of “wise men;” it can be satisfied only through thinking, and the thoughts I had yesterday will satisfy this need today only to the extent that I want and am able to think them anew. » Hannah Arendt10