To start, karma is not the "do good things and good things will happen to you" concept it is portrayed as by popular culture (Okay, it is that definition in that people define it that way in agreement with each other, but that is not what it means in terms of Eastern Philosophy). Another popular reference karma is linked to is "What goes around comes around." A more apt conceptualization would be "What goes around goes around, and around, and around."
Simply put, karma is habit.
It is the idea that what one does will be done again. The concept, in truth, is much more complicated than that. In Eleanor Rosch's course Buddhist Psychology, she presented this idea of karma in great detail, using an ancient version of The Wheel of Karma, which went so far as to break down a habit into 12 steps. We went through each step for a variety of habits, from the basic eating of Dorito after Dorito after Dorito, to how a person with a propensity to sabotage their own relationships maintains that cycle. It is an exercise worth further consideration that I am sure you can find through some advanced Internet searching, should you be so intrigued.
For my purpose, the above is enough.
Professor Rosch then gave us a way to think of Karma in basic terms, easy to understand. We were told to think of any action or thought as riding a bicycle through soft, moist dirt, or mud. The tires leaves an imprint. That imprint gets deeper each time one rides along it, creating a deep groove. That groove becomes difficult to escape once you enter it, and you have created a habit.
Therein, too, lies the key to breaking a habit. If you identify the groove before entering it, it is much easier to avoid rather than trying to jump out of it after the tires are already well within groove. Each time you avoid that groove, you are creating a new groove which avoids the old one. In terms of a habit, each cigarette urge successfully avoided makes it a little easier to avoid the next urge. You are creating the habit to not smoke.
Life is a battle of habits.
The above metaphor brought me an epiphany, laying the foundation for my desire to link Eastern Philosophy with the physical sciences of the West.
"That imprint gets deeper each time one rides along it."
I could not help but see it precisely mirroring how a synapse is strengthened every time it fires, making it both more likely to fire and do so more strongly, each time similar stimuli is experienced, be it a physical sensation of a thought. You will think what you thought before, from a hardwiring of the brain perspective.
Worth some contemplation, you can now envision how a physical sensation can then lead to a memory, which can then lead to a certain state of mind, all from a perspective of mapping synaptic connections. This rabbit hole can go very deep, as the earlier example posed by Prof. Rosch regarding a propensity to sabotage a relationship can actually be mapped out, first theoretically, but maybe some day, through actual synaptic mapping.
Take this into account when considering my previous post regarding the nature of thought. The brain naturally ignores anomalous data, comfortably taking the path it has taken before. Abandoning a theory is very much like breaking a habit. In truth, the mind is stuck in a groove when it ignores anomalous data. Just as you can create a new habit by not smoking when you have the urge, you can create the habit of questioning your presumptions. You can train your brain to question everything.
In my opinion, this is the first step towards finding The Path, realizing so many paths exist.
[In case it takes a while to get where I am going eventually with this, here is a preview. The nerves of the body which stimulate muscles are synapses, too. The paradigm of synaptic strength and "habit" applies. Any physical movement, any posture taken, creates a physical strengthening of the synapse responsible for it, thereby making it more likey to be repeated or maintained. This is a way to think of "muscle memory" on a synaptic level.]