On Inertia

In high school, my excellent science teacher explained the concept of Inertia. My recollection of his explanation was that to get a block of wood moving on a countertop it took more energy to start the movement than to keep the movement going once it had begun. Whether this is a perfectly accurate description or not I do not know, but it stuck with me. Through my engineering degree and into my work and personal life, I have always kept this concept of inertia quite close to my heart.

The main thing I try to maintain is positive movement in the right direction. That is to say, once you get yourself going in a certain direction – at work on a project, in a relationship with a person, or in a situation – it can be very difficult to change the movement of that project. There are multiple factors at play such as sunk cost fallacy where you do not want to stop doing something because you have already invested in it, but inertia is the underlying physical concept that I find most interesting. Once you start something, stopping is harder than you think and continuing in the same direction is the least path of resistance.

To start something new is hard and I think nearly everyone recognizes that. Once you have started you are not incentivized to stop, partly because you know how hard it is to start something new. If you stop what you are doing, you know you are going to have a proverbial hill to climb when you go to inevitably do something new. This fear of the new inertia build up you have to do reduces our ability to change. All that to say, getting started is hard, continuing is easier, stopping and starting again is even harder.

The main point I try to constantly remind myself of is “Is the inertia I have built up in my life moving in the right direction”. Is the momentum I am building up growing and specifically, is it growing in the direction I ultimately want to head in. If the answer is yes, then the key is to keep that momentum going and minimize the risk of going off the rails. A childhood friend of mine once explained that the more you have, the less you should risk.

Risk is itself a vast and fascinating concept, but when thinking about risk I prefer to think of it in two clear ways. First is the regret minimization framework, which explains that you should take a decision based on which decision you will regret least. Life is short and you should aim to lay on your death bed happy that you stretched and reached for the goals and things you truly wanted, not regretting decisions that led you down the path you did not really want. That being said, to make a proper regret minimization decision, you need to understand the risks of a decision. Some risks are clearly known, others are often guesses.

When thinking about the risks of a decision, one nice framework is to put your options into three potential outcomes. First ask yourself, “what is the best outcome that could happen?”, then “what is the most likely outcome that could happen?” and finally, “what is the worst outcome that could happen?”. You can try to estimate the chances of each, but most likely you will end up with the most likely outcome. The main question to ask though is, “can I live with the worst outcome and still be happy?”. If the answer is yes, then you should seriously consider the decision linked to this risk evaluation.

When thinking about the path to take, one might cite Robert Frost’s poem,

The Road Not Taken

By Robert Frost

Two roads diverged in a yellow wood,

And sorry I could not travel both

And be one traveler, long I stood

And looked down one as far as I could

To where it bent in the undergrowth;

Then took the other, as just as fair,

And having perhaps the better claim,

Because it was grassy and wanted wear;

Though as for that the passing there

Had worn them really about the same,

And both that morning equally lay

In leaves no step had trodden black.

Oh, I kept the first for another day!

Yet knowing how way leads on to way,

I doubted if I should ever come back.

I shall be telling this with a sigh

Somewhere ages and ages hence:

Two roads diverged in a wood, and I—

I took the one less traveled by,

And that has made all the difference.

I am not sure Robert Frost had inertia in mind when he wrote his poem, but if you are going to consider what to do, this poem is often as good as it gets. Whatever path we take, the inertia builds up and can keep us moving forward if we so wish. But, when we come to another fork in the road it is critical to ask if we should stop and restart down a new path, even if that means we must build up new inertia and momentum down an unfamiliar path.