It's the idea that you get into a mindset and then for what ever reason, stay blindly in it for too long.
It's the physics definition of inertia that states it best.
- something that stays in it's state of rest or motion along a straight line so long as it's not acted upon by an external force
Mental inertia can be a thing that is either good or bad. It simply depends on the context.
Yes, in my mind-a scary place indeed-life is lived in context. Every experience, every moment has a context that shapes it.
An example of mental inertia being a good thing, or at least a good thing in the context of the believer, would be holding a certain faith belief. I will speak from the context of Christian simply because that's what I know best.
Mental inertia of being Christian looks like this. You believe in the Bible. You believe in God and Jesus. Beyond that it gets into the details and that is a part of the point. Among fellow believers you will be pushed. Your motion of believing what you believe along the straight path of your faith will be pushed at by others who dispute some aspect of what you believe to be truth. This is true also of those who are not fellow believers. An Atheist or a Jew or someone else will come along and push at your path. You, the believer, will maintain your mental inertia and remain on the path, saying your faith is strong and solid. That choosing not to be swayed from your path, is mental inertia.
Mental inertia can be negative in your life if you are, for an example, an addict of some sort. Many people will come into your life and your path of motion, your thought path, will be questioned and pushed. As a caveat, I understand and respect that some aspects of certain addictions do in fact involve a medical issue and it is not simply the mind being "stuck" per say, but... You as the addict may even push yourself about your mental inertia on the subject of your addiction. You might have those conversations with yourself, "I really should stop, I need to quit soon" and so on, but the path has been worn so hard and deep that it is very hard to shift your thoughts out of the mental inertia.
I personally think mental inertia is most dangerous in our own thought patterns and in our relationships.
Let me give you an example from my own day to day life. It's not a big deal issue for me, but it does actually suck some brain energy once in a while and that makes me take notice.
So a little while back we changed up our eating habits around here. Back to healthy living, good bye Diet Coke.
Diet Coke is probably one of my biggest vices in life. And, I gave it up. Over the last couple of weeks, I've had a handful of moments when I've thought to myself, man I could kill for a cold Diet Coke right now. I didn't give in. I haven't let myself have one. Temptation is everywhere, access is easy, no one will judge. In our culture a "slip up" when you go on a diet is an expectation. Here's an extra thought for you though, this is a life style change, not a diet. We have changed our eating habits collectively to resolve certain health issues in our home and restore good health. It was not a "summer-is-around-the-corner-I-want-to-go-to-the-pool-this-summer-drop-10-pounds-diet".
Now, here's the mental inertia part of it. If I let my brain continue to focus and repeat to itself how much I want a cold Diet Coke, it will become a sort of mental mantra. Then whenever I have a free space or moment in my mind, whenever I get a drink or snack, whenever I do what would have been something I normally did with Diet Coke in hand, I think the thought of how much I wanted that Diet Coke it would fast become an obsession of sorts. An obsession of denial. I would be perpetually repeating a longing to myself and feeding myself a diet of discontent. In a matter of days, I would easily be focused on Diet Coke. How to justify having one. Where and when to sneak one. In a matter of weeks it would cause a backslide of our healthy eating habits because one justification leads to another. It's like a self-lie.
The thing that got me thinking about it today was something I watched transpire on Facebook. Yes, Facebook. It's a sort of bane of our modern world. We all love it. We all abuse it a little. We all hate it. It's the the adult version of high school drama all over again. There are cliques and dramas and gossip galore. Even when you're Facebooking "above board", it's right there.
Here's what happened loosely. In my wide circle of friends, there are people who have been undergoing amazing personal changes in the recent past. One of them posted a status today that was almost immediately taken the wrong way by a large number of well meaning people. The status poster is well loved and the intentions were heartfelt good I believe, but it was instantly clear that mental inertia was at work. The status was a very generic statement about the day and how it was unrolling. The responses were all in the same vein. The vein of, "Oh here we go again with the drama and let me talk you down off the ledge because I know you and I know what you need and I know just exactly what you meant in your intentionally vague statement."
Well, here's the thing, said status poster has been through a lot in the last 6 months and grown and changed and generally stopped being the person who would have meant that status in a drama sort of way. This is where the mental inertia came into play. The comments came from people who believe they know the poster well, and in fact, they do and they are even fully aware and have been a part of all the changes and growth but... Their minds were still on automatic. Their fingers typed out the pat response to the drama inducing status, forgetting for the moment that this was a person with a whole new take on life. Even though in the last 6 months their own paths of thoughts about the poster have been continually shifting and changing as the poster grew and changed, in the moment it was right back to mental inertia.
We do it all the time in our lives. It's a part of how our brains work. We have mental inertia about the proper way to behave in public or how to eat or what a friend behaves like. We have it with our families and our budgets and our spouses. We have mental inertia about our accomplishments and our goals and our behaviors.
I'm not preaching that we have to be on a constant fervernt guard about this or that we have to radically change our lives to combat it. Not at all. Some of the mental inertia in our lives is a wonderful positive thing that keeps us focused and functional. But sometimes it is something that bears some self-examination and self-evaluation.