In the absence of a faith I don’t think I’d have very strong opinions about abstract or moral concepts. This isn’t one of those “if you don’t believe why don’t you kill your grandma?” arguments that make good-hearted atheists roll their eyes. I have no desire to kill grandmas regardless of my beliefs, but if I was somehow convinced that it was all just atoms bouncing against each other I’d have a hard time articulating to a psychopath why he shouldn’t (and it’s not just me, read a graduate school-level meta-ethics text to see how hard it is).
This doesn’t necessarily mean that I hold to “Divine Command Theory,” which is the idea that something is good because God says so. (As an aside, Alma 42’s “God would cease to be God” is a strong anti-divine-command theory scripture. It’s clear that there are some moral principles embedded in the universe that God Himself has to adhere to). But rather, that there is some moral, metaphysical scaffolding to the universe, which is a framework that is hard to get to if, again, everything can be reduced to atoms.
If it’s all chemistry then in theory the fundamental difference between Jeffrey Dahmer and Mother Theresa could be a potassium molecule in the brain that didn’t quite make a complete electromagnetic connection. Of course, it’s more complicated than that, but the additional complexity doesn’t change the point. If it’s not free will but mechanics, it makes as much sense to be upset at Jeffrey Dahmer as it does to be upset at a boulder that fell down and crushed somebody.
However, if you ask why that metaphysical moral scaffolding is itself justified, then I’m in trouble, but literally every belief system is in trouble from infinite regress if you continually ask for the whys of the whys of the whys, so at some point we just have to act according to feeling, and that’s okay, but it does limit the extent to which we can be judgey about other people’s intuitions. Logic can help us be consistent in our moral frameworks, but I’m generally skeptical about reason’s ability to construct a moral and meaning-making system from whole cloth.
As I noted before, as a believer in moral “writing in the sky” but not in the Church, I’d be fuzzy on how morality applies to my life beyond the basics of not hurting people, since the “hurting people is wrong” instinct is so visceral. (That being said, there are contexts in which hurting people is the most natural thing in the world for Homo Sapiens).
I’d try to be a nice dude, but I wouldn’t exactly give my body to be burned or live in some hut so as to maximize my ability to donate to anti-malaria bed nets.
In my family growing up we had a saying that “that which isn’t infinite is too small, and that which isn’t eternal is too short,” saying that the only things we should really be concerned about are things that in some way or another tie into the eternal.
In his book Until the End of Time: Mind, Matter, and Our Search for Meaning in an Evolving Universe Columbia University physicist Brian Greene quotes an interesting thought experiment (paraphrasing, since it’s been a while since I’ve read it) where they ask how what we think is meaningful would change if the universe were ending tomorrow. He then asks whether it makes a difference whether the universe was ending in a year, 10 years, 100 years, or a million years and then drives home the point that, since those increments are really basically the same compared to the eternal blackness afterwards, the end of the universe raises uncomfortable questions about why anything matters. (Contrast this with the very Latter-day Saint cosmological point made by non-Latter-day Saint scientist Freeman Dyson that “no matter how far we go into the future, there will always be new things happening, new information coming in, new worlds to explore, a constantly expanding domain of life, consciousness, and memory.”)
A similar note is struck by PD James’ fictional book Children of Men, that takes place in a world where a disease causing mass sterilization is causing humanity to amble towards oblivion. If there is no future, how much would our strivings change? These thought experiments make one realize how much of our meaning making is pinned onto something continuing indefinitely into the future, even things we wouldn’t immediately think of that being true for.
On that note, I’m still kind of surprised when some of my friends and colleagues in academia leave religious belief and then continue to be really preoccupied with their impact factor or what such and such top scholar thought of their work. If you think it’s all consigned to eternal black oblivion then it seems like the ozymondian nature of such clear artificial constructs as the honors of men should be obvious. With faith there’s at least the idea that such constructs are still attached to eternal verities and virtues that will continue after we’re all maggot food. I get that people need meaning in some form or another, but with just a little bit of introspection people would realize how hollow sacrificing for abstractions based on artificial constructs is.To be honest, I feel like my fellow millennials kind of grasp this, which is why older generations pull their hair out about us turning our back on the deal where we work hard for a half century with two weeks a year off for the pyramid-scheme chance at the C-suite and a well manicured lawn in a nice neighborhood.
In terms of specifics, all of this is to say that if I left belief in an afterlife or some other eternal meaning, I would basically strive to have a fun life (again, without hurting anybody). I score pretty high in sensation seeking, so for me personally I would to stuff as many unique and novel sensation experiences as possible into life.