In physics “momentum” – the product of mass and velocity – can be thought of as an object’s capacity to resist changes to it’s motion. A heavy truck going fast has a large momentum and therefore requires a proportionally large force to stop. A small ball rolling slowly has a very low momentum, and is proportionally easy to stop.
I posit that there is such a thing as “habitual momentum” – the inverse of the product of time and discipline – which equates the capacity to maintain changes. The longer you have maintained a habit or the more self-discipline you have, the less likely you are to stop your particular habit.
Thus, one can offset poor self-discipline through time, and over time, proportionally less discipline is required to maintain a habit.
(I suppose physicists don’t think like typical people, huh?)
Now, just like physical momentum, I believe that habitual momentum is conserved.
This explains why it’s very, very difficult to make many, many changes all at once. Most people do not have the necessary reserves of self-discipline to change more than a few habits at a time. Radical change – such as simultaneously trying to wake earlier, eat right, exercise, stop smoking, discontinue cursing, and starting brushing your teeth at night – are destined to ultimately fail, and only if you’re lucky will one or two of those positive changes stick.
The conservation of habitual momentum tells us that as we maintain a goal over time, we are able to more efficiently utilize our self-discipline reserves for working on other habits, and therefore utilize more of our constant momentum for other things.
[To my fellow physicists: please do not attempt to construct a relativistic version of this theory, you’ll give yourself a headache. ;-) KM]