Ok...fair warning. I may ramble, and my arguements may be incoherant.
There are also two predicates for the arguements, which if not accepted, destroy the arguement, so please don't post criticism based on these two points (except to debate them in and off themselves) because I know the arguement relies on them:-
1);- Good and Evil are subjective concepts, until and if we know the absolute definitions of each - everyone thinks that they are doing 'good', even if no-one else agrees.
2:- There is some form of supreme guiding/creating will behind existence. (ie 'God' in some form or another).
Ok:- Firstly, moral law. Is it actually possible to violate moral law while still remaining within your nature? I don't think so - because that nature was created by the supreme being to be as it is - and so by following it, you are surely following the 'morally correct' path. Of course, if the supreme being doesn't know the absolute meaning of morality either, then you have a problem, but still. This has two associated problems:- firstly, to determine whether you are acting 'correctly' - i.e. within your nature, you actually have to know what that nature is - and I don't think many people can claim to say that, beyond a few words (eg 'artist'). The second problem is that it can be used as a claim that all actions are moral - here, though, there is an answer, because although following our basic natures may be moral, misinterpreting the needs of that nature is not - take Hitler, for example (I can't think of a less blantant one at the moment, sorry). Now, assume that his 'nature' was loyality to his friends, patriotism, and mysticism (among other things, obviously). Following these, as he did, he would have been acting 'morally'. However, he took these to extremes, and created a cult religion, and tried to set up his country as the preminant amongst all others - not to mention killing millions of people. Hence, he did not act morally. Unfortunatly, it can be argued that certain people (such as murderers, or warmongers) are acting within their nature, and so, according to the above theory, are acting morally. This is a problem I haven't worked out as yet.
The other side of the coin, then, is social law. Since we cannot ever hope to understand absolute moral law, nor can we objectively determine someone's nature, some other system had to be developed - social law. This is the more straightforward part, since everyone is familiar with their countries laws.
The real question, though, is in daily life, which should be considered the more important? What you feel to be morally correct, or what the majority feel to be morally correct, as expressed through social law?
Did that even make sense?