Section I attempts to determine whether there is a moral law.

Section I clarifies common moral concepts, focusing on 'good will', 'duty', 'respect' and 'law'.

Section I clarifies why it must be immoral to act from egoistic motives.

Section I defends Hume's distinction between relations of ideas and matters of fact.

Section I presupposes that there is a universal law of morality and asks:  What would its content be?