Inertia
Physical inertia is the tendency of an object to maintain its velocity unless a net force changes it. Used as an analogy for habits and organizations, it prompts us to ask what sustains an existing pattern and what would make a change easier.
THE IDEA
Inertia
Starting something is hard, but so is stopping something. In physics, inertia is resistance to a change in motion. Newton’s first law states, “An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.” A planet needs no engine to keep moving, but gravity continually changes its direction, producing an orbit rather than straight-line motion.
Galileo’s inclined-plane illustration helps explain the role of friction. A ball rolls down one plane and up another. The smoother the surfaces, the closer it comes to its initial height on the opposite plane. Reducing friction lets the motion continue farther; friction is a force opposing it.
In Principles of Philosophy, Descartes states that “each thing, as far as is in its power, always remains in the same state; and that consequently, when it is once moved, it always continues to move.”
Inertia offers an analogy for habits and organizational routines. Familiar practices can persist because changing them takes effort, introduces uncertainty, or requires coordination. Maintaining the status quo can also take work. Neither behavior is a direct consequence of Newton’s law.
The analogy suggests looking at what makes a change difficult to start and what helps it continue. Repeatedly switching tasks can impose costs of reorientation, so uninterrupted work may be more effective for some activities. Those costs are a cognitive issue to examine, rather than something established by physical inertia.
Commuting patterns, jobs, and difficult conversations offer other examples. A person may stay with a familiar option because it is easier, but money, infrastructure, obligations, and available alternatives also matter. Calling a pattern inertia is a starting point for investigating it.
« For, like a mass in Newton’s first law of motion, once our minds are set in a direction, they tend to continue in that direction unless acted on by some outside force. »
Leonard Mlodinow
When to use it
Overcoming procrastination by setting small, easy initial steps to overcome the resistance to start.
Designing change management initiatives that account for employee inertia, using incentives or clear communication as the external force.
Developing habits by leveraging momentum: once a positive habit is in motion, it requires less daily effort to maintain.
Reducing task-switching in work environments to avoid the cognitive inertia costs, improving overall productivity.
FROM THEORY TO EVERYDAY LIFE
In practice
Galileo's inclined plane experiment
Galileo demonstrated inertia by rolling balls down inclined planes; smoother surfaces reduced friction, showing objects maintain motion unless opposed.
Task-switching costs
Moving between demanding tasks can require time to reconstruct context. Reducing unnecessary switches may help; the comparison with inertia is an analogy rather than a physical explanation of the cost.
Resistance to lifestyle changes
A familiar commute, job, or conversational habit can persist because changing it takes effort or carries uncertainty. Practical constraints and available alternatives also need to be considered.
A MOMENT TO REFLECT
Put it to work.
What current habits or routines in your life are being maintained by inertia rather than conscious choice? How might you apply an 'unbalanced force' to change them?
Think of a project you've struggled to start. What kind of 'friction' (obstacles) can you reduce to make the initial push easier?
In what ways does your organization or community exhibit inertia against beneficial changes? What strategies might create the necessary external force?
References
- Principles of Philosophy — René Descartes
- Quote in sidebar — Leonard Mlodinow
CONTINUE THE CONVERSATION
Source texts
- The Great Mental Models Volume 2 Physics, Chemistry and Biology