I have a couple of comments on your exchange with the Satanist. First, logic certainly doesn't seem to be a big thing for him. He doesn't even recognize what a contradiction is. But self-deification comes through in his answers. Secondly, he did try to express a concept that may be legitimate as a rule for behavior. He denied the existence of an absolute moral standard based on right or wrong from God, but claimed a standard based on consequences. "If you do this it will only hurt you." He called it Karma and common sense, but I believe God uses that motivation, alongside the right and wrong motivation. "In the day you eat of it you will die," "Those who love money pierce themselves with sorrow," etc. Isn't it possible to arrive at some universal guidelines for behavior on the basis of consequences, apart from divine Law?
Thanks for the feedback on the conversation with a Satanist. I agree that God does use the fact that sinful behavior has negative consequences as a motivation. But I wasn't addressing the issue of motivation. I wasn't claiming that one should be motivated to perform or abstain from a given act on the basis of what is right or wrong. Rather, I was trying to get him to think about what best explains the fact that we can't help thinking and speaking in terms of objective moral truths.
The point I was trying to make was that even if we observe that a particular action yields harmful results, it doesn't follow that that action is morally wrong. At best, we can conclude that it is imprudent. Yesterday I broke out with what I believe is an allergic reaction to something my wife used in the wash. This morning when I was trying to decide how many Benadryl tablets to take, she said that I shouldn't (or ought not) take two because that would make me very drowsy. I decided to heed her advice but it wouldn't have been immoral or blameworthy of me had I decided to take two. The "ought" in her counsel is different from the "ought" in the statement "You ought not steal from your neighbor" as the latter "ought" conveys a moral prescription. Sure, pragmatic considerations can be helpful guides for behavior but they're not necessarily moral rules one is obliged to obey. Moral obligation requires some kind of moral authority. The Satanist, while denying the existence of a moral authority, expressed moral outrage as though some universally binding moral standard had been violated. This is why I wanted to press him on his likening urinating into the wind to doing violence to someone. He wanted to say that both are stupid acts with undesirable consequences yet it was clear that he made a moral distinction between them.