PART I<quoted text>It must lie in a difference in personalities. For me, if we can't know a thing for certain, what's the point of addressing it at all? What good does it do us to assert an absolute must exist, while acknowledging we may not know for certain what it is?
I don't think it follows that if there are no absolute truths than anything goes. Actually that's pathological thinking. Back up now - not saying you're pathological for proposing so, you're just formulating an argument for absolute truth. I just disagree with your path to that conclusion. Societies agree in concert the basics of right and wrong. Those societies that disagree over those basics, generally don't play well together.
It might seem to be an absolute truth that murder is wrong. Some things are universally agreed upon, at least at core. At it's most basic concept, taking a life is murder. Recognizing murder as a wrong is universally realized to be, if not "truth", then at least socially beneficial. But we quickly add qualifiers to that concept, and equivocate what constitutes "murder". We ourselves cause this absolute truth to be relative. I don't think it can be both things at once. Very few societies have managed to reject the taking of life in total, at any time, for any reason. No major society, philosophy, or religion has done so. Therefore it seems that murder as a concept is universally recognized, but what exactly constitutes "murder" is relative.
If I lived alone on an island, there would be no reason to elaborate sets of rules. I am free to decide for myself what is right and wrong. It's when people chose to live together in groups that a social structure became necessary. It's a fundamental of society to decide together what is right and wrong. They decided that taking a life within the group was detrimental to that society. Taking a life from that group over the hill? That's where it gets murky, and little has changed over the years, no matter the "absolute truth" each allegedly adheres to. Nonetheless, a basic concept of murder has been universal across all time, and all societies, from the savannah to the city. Thus we can say with validity that flying a plane into a building is unacceptable to society at large, no matter the certitude of the perpetrator. It's not an absolute, because we can and have rationalized the taking of life ourselves as the situation arises. But it is an accepted truth.
There are certain absolute truths - we need air to survive, gravity sucks, the actual cost of a repair is always more and never less than the estimate, the phone always rings just as you sit on the pot, and so on. But I've yet to see an absolute truth in social structures. Just accepted conventions.
I agree with some of what you've said, so I'll confine my reply to the points where I don't.
1. First and foremost, you said "if we can't know a thing for certain, what's the point of addressing it at all?" You surprise me, Hip. Isn't it obvious that when we don't know for sure what is right and wrong, the point of addressing it is TO FIND OUT?
2. Im not talking about absolute TRUTH here. I am speaking of absolute MORALS. That is a separate issue, although I grant you it is closely related. One of the most damaging and most pernicious lies of the times we live in is that there are no moral absolutes, it all depends on your values/worldview, etc.(By the way, I remembered yet another name for this poisonous nonsense,situational ethics.)