My Answer Pt. 1
You guessed it, I think I have found an answer!
Before I spell it out let me put two possible cosmologies before you.
Only two because most of those held by 'primitive' peoples (such as the Australian Aborigine’s 'Dream-time' stories) are not tenable in the face of modern scientific knowledge. Which historically has had a devastating social impact on these peoples when the scientific world came to their doorstop in the form of white settlers.
So my two cosmologies are:
Atheist: there is no God, evolution is our maker
Theist : there is a God, evolution probably but not necessarily true.
They are of course mutually exclusive – if one is true the other must be false. However both are, from a sociological point of view viable cosmologies in the modern world.
I am only concerned with the question “how do we justify saying 'this is right / that is wrong'” at present. So let us see how these two stack up on that question.
1. If there is no God
a) All religious reasons for ethics vanish as the required justification.
Of course religious appeals not disappear. Throughout human history those in power or seeking it have appealed to religious beliefs or feelings for legitimation of their position. But in this scenario they survive purely as a method of persuasion at times when religious belief has or does exist. They are just part of a leader's bag of tricks to stay in power, just “the opiate of the masses”.
b) If evolution is our maker, does it also set the moral rules, if of course evolution has any morals?
As I said earlier, the fact is we humans DO have moral values and make moral judgments. I will take here those I know something about – the common moral sentiments of the English speaking peoples. How do some of these compare with evolutionary exigencies?
Evolution is survival of the fittest. That is its basic mechanism. But the world reacted in horror to the Nazi experiments in eugenics. On a smaller scale, half my children would have died but for antibiotics. I am totally thankful to modern medicine for their survival. But from an evolutionary point of view the weak should be allowed to die out.
In evolution the survival of the stronger gene strain is paramount. So the young lion who succeeds in driving the old lion out proceeds to kill all the cubs of the former alpha male. In lions we do not think that immoral – that is just evolution at work. But in humans we feel differently. It is tragic but true that among step-fathers (and in fairy-tales wicked step-mothers) there is a much increased risk to children of the previous 'husband'. That has echoes of evolution – but is morally abhorrent in our societies.
One could go on looking at examples, but I think the point is clear – that our concepts of right and wrong did not come to us through evolution.
This leaves the very real moral feelings we do have as some sort of social construct. So socialization, appeals to religion (if that works), appeals to emotion, good old propaganda or scholarly philosophical discussion all boil down to being just tools of persuasion.
“right and wrong” are simply what some person or persons have been able to inculcate by whatever means into other people.
Which I suppose is in a quirky way evolutionary: “might is right!” (in this case “might” is the ability to influence people and hence change social mores.)
2. If there is a (real) God.
a) There is a higher point of reference. Evolution may still explain the origin of the species, but it does not have to explain our moral sense.
b) There is still Plato's dilemma: “Is it right because the gods command it or do the gods command it because it is right?” Good point – particularly considering the morals of the supposed Greek pantheon of gods.
But my answer is this:
Suppose God has a moral nature: Say God is the very epitome of love, justice, mercy, kindness, faithfulness. Say God has an innate moral revulsion to cruelty, unfaithfulness, robbery, oppression, murder, lying. Suppose again that in some way humans have inherited at least a pale shadow of this nature.
If God then gives commands such as “love your neighbour as yourself” or “do not commit adultery” which are expressions of God's moral character then it is simultaneously true that God commands it because it is right and it is right because God commands it. And Plato's objection disappears.
More than that: just as the “standard metre” in Paris is a standard by which all other metre rules can be checked. God's moral character is the absolute standard of morals.
In our parable the contestants could not directly access the standard in Paris. But they did have derivative standards – measures that had been checked against other measures right back to the real metre.
So with humans: Our knowledge of God's character is only partial. Also if Aristotle was right about the unity of the virtues, then God is, for instance, simultaneously perfect love, perfect mercy, and perfect justice. How humans could embody this in a particular instance may be incredibly complex. I do not mean to say it is impossible, just that it is ever so much more complex than using a metre rule!
But ….. more next week!