There’s the atheist joke that “Christians are announcing that without belief in Hell, they would be horrible people” or something to that effect.
Sad thing is that there indeed is truth to it, and it has consequences. As much as I dislike organized religion and on practical level, would align with scientific, materialist worldview, I do think that without straight forward “be good or be punished” paradigm, a lot of people will be exactly the kind of self-centered assholes we currently see in positions of power in the world.
Back in the day, rich people would fund hospitals and schools in hopes of getting to heaven. These days why bother, religion is mostly a cultural artifact to occasionally pay some lipservice to, while one fully believes that their material possessions are all they got, and even their lowest possible pleasures should be attended to with whatever resource they can spare. Scientific materialism helped get rid of a lot of assbackwards reasoning but with cold hard logic, came the ease of reducing everything to a number. Money, usually. Worth. Nothing else matters. You can’t put a number on love, care, kindness, or something as ephemeral as “goodness” - an ever moving target which is only ever defined by the person using the word, with luck at least slightly informed by (pro-)social contracts. Indeed most people would specifically reject any attempt to put a number on those qualities as it would run counter to their virtuous nature. Which just makes it easier for those with power to devalue those qualities entirely, and with power, build structures that lets them indefinitely get away with it.
I think what is supposed to replace the belief in hell for some people to act well in modern societies is police and justice. Not always working, but maybe still an improvement.
The problem is science can’t tell you what is morally good or bad. I think Human Rights is the best guide we have in terms of a fairly well accepted consensus of what is good for humans.
What is good and bad is in most part established through natural law. You can’t merely rely on others to tell you what human rights are, as that consensus can be manipulated. Being moral requires empathy and integrity. To see how your actions impact others and whether a world perpetuating your behaviors flourishes or falls into destructive chaos.
Aren’t Human Rights the best outcome so far of the supposedly “natural law”?
The concept of natural law is probably even easier to manipulate. Some used it to justify slavery for example.
Listening to a pretty much world wide consensus of what is good for humans is a pretty good way to reduce your own biases and the already existing effect of manipulations on your morality.
Empathy and integrity are struggling against other less positive instincts (fear, greed) inside humans heads, and it’s rarely clearly labeled. So I think it’s good to have a consensual guide to sort the thoughts out.