It could be argued that "basic assumptions around situational ethics are arbitrary" - Exactly - unless you have some kind of a measuring stick that is truth! (which I have and you don't!
) I will not agree that pleasure is preferable to pain, or that health is preferable to disease, etc. - I absolutely not will agree with your "bedrock assumptions"
Wow. Physical and emotional health is not preferable to physical or mental disease? That tells me everything I need to know about your position. How do you explain that one to your teenagers? The sad fact is that the dominant thinking of the last 2000 years, Christianity, has been inconsistent about improving human welfare. Which is why humanism has done more to reduce human misery in the last 100 years than Christianity has done in 2000. Of course there are Christian Charities who try to alleviate human suffering but that seems to contradict what you just said. Do you want to help people practically or not?
And what you are saying Christians do to convince their teenagers is another assumption you make which is not how I operate at all with my teenagers.
Which just demonstrates my point that the Bible is useless at helping us with everyday moral dilemmas and practical problems.
I disagree that the scientific method is the best way - in fact at a different place you admitted that 100% truth cannot be undisputedly found using the scientific method. And you have never answered how we can use human reasoning as a basis when "human reasoning" came about by random processes.
This is essentially the Argument from Reason. There are various rebuttals to it but i think quite a good one is from Dr Richard carrier below:
"But it all reduces to a simple Bayesian case against God: if God did not design us, our innate reasoning abilities should be shoddy and
ad hoc and only ever improved upon by what are in essence culturally (not biologically) installed software patches (like the scientific method, logic and mathematics, and so on), which corrected our reasoning abilities only after thousands of years of humans trying out different fixes, fixes that were only discovered through human trial and error, and not communicated in any divine revelation or scripture. But if God did design us, our brains should have worked properly from the start and required no software patches, much less software patches that took thousands of years to figure out, and are completely missing from all supposed communications from God.
Thus, observation confirms that the
actual evidence of human reason is far more probable if God did
not exist than if he does. Thus, even the Christian’s own Argument from Reason argues that God does not exist, rather than that he does. Because once again, when we bring in
all the evidence, the Bayes Factor strongly supports atheism."
Now here you switch and say "instinctively most of us know" - so are you are suggesting that the "instinct" of the majority (most) is what determines objective truth? What are "good" parents? How do you know what a "good" parent is? My idea of a "good" parent is obviously very different than your idea? Are you right and I am wrong?
We should communicate with people honestly and try to understand if they are happy or whether they could be more happy being or doing something else. According to the New Testament, a slave is "more blessed" if their master treats them badly. I find this perverse.