Possible answers (entirely dependent on ones upbringing and disposition):
* out of concern for the well being of others;
* out of recognition that it is in ones nature to do so;
* because one holds oneself (for some reason) to objective standards (which apply in the current circumstance);
* because the feelings or well being of the person(s) affected by ones choice are held to be precious;
* because one is a sentimental, even romantic, humanist;
* because you would hope to be shown the same consideration were the roles reversed;
* out of dumb habit;
* for no conscious reason and because one allows for some whimsy;
* because the cost in inconvenience in the current situation doesn't weigh too heavily against acting morally;
* because there is a good samaritan law in effect with repercussions which one would want to avoid;
* because the legal repercussions provide a sound incentive in the current circumstance.
By no means exhaustive but it certainly looks as though there could be a multitude of reasons not involving an ultimate rule-giver.
* out of concern for the well being of others;
* out of recognition that it is in ones nature to do so;
* because one holds oneself (for some reason) to objective standards (which apply in the current circumstance);
* because the feelings or well being of the person(s) affected by ones choice are held to be precious;
* because one is a sentimental, even romantic, humanist;
* because you would hope to be shown the same consideration were the roles reversed;
* out of dumb habit;
* for no conscious reason and because one allows for some whimsy;
* because the cost in inconvenience in the current situation doesn't weigh too heavily against acting morally;
* because there is a good samaritan law in effect with repercussions which one would want to avoid;
* because the legal repercussions provide a sound incentive in the current circumstance.
By no means exhaustive but it certainly looks as though there could be a multitude of reasons not involving an ultimate rule-giver.
