The 'sin' is its own punishment
Or: morality as not actually being optional
12-step recovery meetings often open with a reading of the aforementioned 12 steps themselves, which are presented as ‘suggested program of recovery’. The word ‘suggested’ is emphasized, with a bit of a smirk - the steps are suggested in the sense that it is suggested to use a parachute when jumping out of a high-flying airplane.
The steps have to be mere suggestions because nobody can ever directly force anybody to do anything. You can threaten people, but they can still choose to disobey you and accept the punishment. You can jump out of an airplane and see the ground rushing up to meet you and still freely choose to not pull the chord on your parachute.
However, just like it’s impossible to fall from an airplane without a parachute and get away with it, it’s also impossible to be a bad person and actually get away with it.
For example: If I lie, the other person may accept my lie as truth, but my action creates a separation between me and them and everyone else I lie to. Without integrity, I dis-integrate - my emotional energy gets split up between multiple versions of reality, my identity becomes fuzzy and unfocused and incoherent, and things just start to suck for me. Everything I do for temporary gain and self-preservation actually makes things worse for me as an individual, because it pulls me apart as a human being and disconnects me from human community.
So, as I see it, being a better person is necessary on a mechanical level. I have to be a good person in the way that my heart needs to pump blood - I technically have the option to rearrange my heart to do something different, but then my body would fail. I technically have the option to lie and cheat and steal, but then my human existence would fail in much the same way.
It’s not the case that if I live as a bad person I’ll maybe someday get struck by lightning by an angry god, or that I’ll burn in hell forever when I die. There’s no disconnect between being a bad person and suffering. The sin is its own punishment.
This is one of the ways that I see it as fruitful to secularize the idea of ‘sin’. Secular ‘sin’, to me, is twofold - we lead a sinful existence in that we are finite beings who are condemned to ignorance and weakness and failure and eventual death, and we undertake sinful actions when we do things that create unnecessary disconnects between us and our fellow suffering human beings.
I must hasten to add here that there’s no disgust here, at least not for me. We are not required to recoil from our sinful nature, nor do I think there is a judgemental god spitting on our souls from on high. Indeed, accepting all of the above has been step one in leading a better life for me. Being human means not having any reason to expect ourselves to be superhuman. Nobody gets life right on the first try.
I must also hasten to add that seeing some value in the idea of secularized sin doesn’t mean that we should sprint to ancient texts to follow their admonishments to the letter. I think we can take inspiration from any source that works for us but at the end of the day we’re the ones who are living and who have to figure out life as it is for us. What worked for one generation isn’t guaranteed to work for the next. It also isn’t guaranteed to become outdated! Progress isn’t inevitable and neither is decay.
What works for me is integrity and community - trying to be an integrated human being, speaking my truth and keeping my commitments, giving help when I can and asking for help when I need it. However uncertain human life is in our finitude, it becomes much more workable when we don’t try to work it all out on our own.