"Selling your soul" sounds like a tremendously dramatic thing to do, but what does it mean?

Go ask whichever house of faith what the spiritual/metaphysical implication of selling your soul might be, but here's the here-and-now definition for the material world: when you sell your soul, what you're doing is changing a foundational belief. It doesn't sound all that fancy, does it? Foundational beliefs, the ones that lay under everything else you think about everyday, aren't actually very complex (if at all). What's freaky is how such simple things can massively warp how you see yourself and navigate the world.

• Are people fundamentally good?
• Can things truly change in a meaningful way?
• How important is money?
• Do you have to justify your own existence?
• What is the purpose of being alive?

These are some examples of foundational beliefs. How you answer these questions affects everything from daily habits to lifelong goals; even down to split-second decisions. The differences between what two people believe can make for astonishing conflicts. Someone that has "I can directly make the world better" at their core will contrast wildly against someone carrying "I am a subject of the world."

What's devious about selling your soul is how easy it can actually be. You can sell your soul on accident if you're not careful! In fact, the world's most enthusiastic buyers love getting souls without the seller even knowing!

Every single moment of your life provides feedback for the choices you make. The more feedback (good, bad, or neutral) you receive, the more reinforced your perspective regarding those choices will become. Pretty simple, yeah? Do more, know more: what's this gotta do with souls? The thing is, for all the preexisting reinforcements you may have, you can start piling up new feedback (and new reinforcements) fast. Imagine walking down a hallway. Your mind will down a series of phases:

1. Explicitly Conscious: I am going to walk down this hallway.
2. Consciously Relieved: I did not immediately die.
3. Growing Comfortable: Nothing unexpected is happening.
4. Functionally Automatic: I will reach the end of this hallway.
5. Completely Ingrained: What will I do after I'm at the end?

It doesn't take but a few (physical walking) steps before you've blown all the way through to step 5. Other decisions happen the same way. You take an action with your thinking mind, then you focus yourself on the reactions as they come. None of this is to say that old habits can be overridden and overwritten at the drop of a hat. The warning is that the point where a "new habit" becomes an "old habit" comes faster than you might expect. If you're challenging a truly low-level foundational belief, there'll be fewer other beliefs and processes to conflict with that would pull you back into the patterns you already knew.

Compounding is freaky stuff. You start telling yourself something new, and the little knock-on consequences of that will start piling up like the price at a gas-pump. First you're saying "I want to feel the burn in my lungs from a run instead of a sore on my butt from sitting," next thing you know you can't even remember the last time you spent a whole day vegged out on your couch watching dumb shows. You start with saying "a little rush from this drug here will get my head cleared up," and you end up throwing your whole life away to feed an addiction. In both cases, you wouldn't even be able to remember the exact point you crossed that line into being a completely different person. In both of those examples, the core belief being changed could be something like "I'm not active" and "the future matters," respectively.

That's what "selling your soul" means from a purely secular perspective. What it does can be absolutely amazing or horrifying, so it's best done with some degree of caution. Thankfully, if you don't like any particular "deal" you make, you're welcome to "buy it back" at any time: easy come, easy go; but easy go, easy come as well. For all the dangers that come with selling your soul, the biggest one is thinking you can't do it: for what it's worth, I strongly recommend pawning off that bit of soul at your earliest convenience.