> I'd like to clarify what I'm arguing here. I'm not arguing that only religion can provide a moral code.

I am sorry if I misunderstoo your position or possibly mixed it up with what al_mandi said. He was the one who stated it is only religion that can give us morals and without it we'd be a barbaric society and living like animals.

> - Science is not in and of itself a moral code. NB: science is not the same thing as rationality!

I would agree with this. Science uses rational thought to build knowledge about reality.

> - Creating a moral code as comprehensive and useful as those that religions provide, based on nothing more than logic applied to a handful of axioms (first principles), is really hard. Maybe not impossible! But it's definitely harder than it looks, and this can easily lead to bizarre and destructive conclusions, or arguments that sound logical on the surface but which actually contain fallacies.

I would also agree here that building a moral code from axioms is a lot of work and hard. And it has to be because there is a huge amount of situations in life for which the moral code would need to be queried for guidance. But wouldn't it provide an immense value if we did all that work and it turned out to be workable? The problems you listed exist just as well in moral code derived from religious axioms.

> You are arguing (I think) that the codes provided by religions are totally irrational and should be discarded

No, I would not say that all of the moral code provided by the various religions are completely irrational and should be discarded. There is a lot of guidelines that I would probably agree with. I just reject some of the axioms like the existance of god. I can agree with a conclusion even if I disagree with how they arrived at said conclusion. Note that I do not claim there is no god. I am not an atheist. But I see no proof for it and we just don't know if there is one or not. It is not proven and it seems not falsifiable.

> If you accept the axioms (e.g. that the word of God/Jesus is axiomatically moral, that the Bible records the word of God/Jesus), then the reasoning from that point on is pretty straightforward.

I don't accept these axioms.

> And in particular it's fairly complete because the Bible covers how to treat a lot of common situations. We know this moral code sorta mostly works, because it's been around a long time and we have a lot of experience with it.

Sure, it might sorta mostly work but at that point we could also have just come up with random moral rules and tried them all over a long time and stuck with the set that sorta mostly works. We would not need to justify them with religious axioms. I think you will agree with me here because you also said religion is not the only way that can provide a moral code.

> We also know what happened to communist societies that deliberately erased religion and replaced it with Marxist morality - hundreds of millions of deaths,

I don't think the soviet era was following the core spirit of science though. It had a lot more in common with religious doctrine. That they pushed to erase religion was rather a play in order to remove any competing power systems that could endanger them.

> The problem is that this justification fails in the case where one side is overwhelmingly strong. If my side knows about guns and has them, and all you have is spears, then realistically I can kill as many of you as I want without any real risk. Moreover I can then move in and take all your land and women, so at that point it's an evolutionary fit strategy to do so. Yet this shouldn't be considered morally OK merely because the risk of dying in return is very low. Indeed, it's critical to have a moral code that doesn't involve relative risks here to stop exactly that genocidal situation from occurring.

I have actually already addressed this. Your argument overlooks that the two groups belong to a bigger group which again needs to optimize for survival. If one part of a species kills another part of the same species then the species has weakend itself. This goes all the way up to all living things. It is an often held misconception that survival of the fittest means it has to be a contest where the winner is the last man standing. If we killed every living being that might be a threat to us no matter how remote then that would actually harm ourselves because it destroys large parts of a working ecosystem and would create all kinds of unforseeable, possibly fatal problems. Religion might arrive at a similar view by proclaiming god has declared life sacred because it was his creation. To me, this while being a useful thought can create a lot more issues because it is intellectually lazier and when people don't understand or are even allowed to question "why" then they have a higher chance of applying the rule in a destructive way. One has to be concious that no rule in a moral code must be assumed 100% correct in all situations.

> Correct but I've never claimed 100% consistent or even majority behaviour; it'd be irrelevant to my argument to do so. My point is that if you build a Darwinian moral code then there's nothing really wrong with me fighting and killing you. After all, animals do it sometimes. Sure not all the time, and I wouldn't go around killing people all the time anyway for the risk related reasons you previously highlighted. But so what? If evolution is all there is to it then how could anyone tell me not to kill you for moral reasons? The fact that most of the time, animals don't do it? Not convincing.

My previous paragraph gave some more explanation on my point of view. To specifically address your example: you killing me for arbitrary reasons poses a risk to you. Society will see your behaviour as destructive to itself and will try to prevent it or punish you for it. This does not mean that killing is always bad. Killing someone that is about to kill other people for no reason would be justified.

Animals don't have the same cognitive capabilities that we have. Nonetheless nature has baked into them traits that are common and result in a lot of behavior that one could reasonably argue that they must have some kind of moral code as well. Human morals are more sophisticated but there are similarities. Now, we are surely not the be-all end-all of evolution which means our cognitive capabilities are also limited. Maybe in a million years our ancestors will look back and pity us for our limited understanding and poor morals :)

At this point I'd like to thank you for a much more intellectually interesting conversation. I was a bit exhausted after the one with al_mandi.