Natural Principles
So we should all serve God in enriching our shared life. But can we generalise about proper ways to do this, or can we only say "Follow your conscience"?
Whether we admit it or not, we are all aware that our awareness of right and wrong applies to actions not just to intentions. In other words, there are natural principles of conduct that apply to all people.
There is serious debate about what these principles are, but not about whether they are. It is possible to say "There are no natural principles" in a debate, but not to abide by it in real life. See how easily those who deny natural principles slip into appealing to natural principles by saying something like "We should not believe in natural principles"!
These principles are inherent in human life, not artificially imposed on it. They guide us intro fruitful paths. Following them restricts individual choices but enriches human development.
(Situation Ethics) "Every situation is unique, so what is right cannot be discussed in generalities."
(Ethical Subjectivism) "Every individual is unique, so nobody is in a position to judge the morality of another's actions."
(Cultural Relativism) "Every society has its own principles."
Societies apply the principles in various ways, but never deny them altogether. When did you last hear someone seriously advocating inaccuracy or treachery? However nonjudgmental we think we are, there are aspects of human conduct that cannot even be described without invoking these principles. If you doubt this, suppose that A has made a promise, and try to think of a way to tell me what happened without implying that A is bound to do something. It can't be done. If they are not bound, they did not promise. You can if you wish deny the possibility of making promises, for instance by claiming they are just predictions, but we all know the difference between a prediction and a promise; the difference is that if you promise you should fulfill.
(Ethical Naturalism) "There is no need to invoke principles from outside ourselves. The principles are based on our all being one family through having common ancestors. Or they are based on similarity, and if apes or computers are sufficiently similar they apply to them too."
Neither of these is sufficient to create such a principle (though similarity certainly seems to be a necessary condition). The basic problem with all such theories is that there is no reason why similarity should imply duty. We can't get an ought from an is, except in trivial cases like "it is our duty to do x". (John Searle claimed to do so in Speech Acts (1969), but he was cheating.)
(Christian Sentimentalism) "God does not impose rules on us. The only principle is love. No other principle is important enough to divide us. Christian love ("agape") is a special quality that Christ gives to the new humanity, expressing itself in all their actions, involving geniality and generosity but also much more, impossible to pin down but discernable by God's friends, indeed the chief sign by which they recognise one another. All ethical principles are secondary compared with this, and it is intolerant to exclude anyone on the basis of such principles.
All Sentimentalists tend in practice to regard others' principles as unimportant, but not theirs. But let us examine the Christian form of it.
They seem to identify agape with self-satisfied sentimentality. It is easy to fall into this trap if we allow ourselves to be influenced by the sentimental aspects of the English word "love". The baloney about "we can sense it but not pin it down" acts as an excuse for declaring folk to be welldoers regardless of their conduct. In the New Covenant Book, agape (active benevolence) shows itself by proper choices, not by good wishes. See The Epistle of James 2.14-18. James' ironical challenge to "Show me your heeding apart from your works, and I by my works will show you my heeding" alerts us to the fact that it is impossible to perceive that heeding Christ except by observing their actions.
"The appeal which men make to the essential life, as distinct from the material facts of conduct, is generally prompted by a desire to assert their own subjectivity and to elude an absolute and objective judgment."
Hegel, Encyclopaedia, Zusatze to "Paragraph" 112.