The writers of the Declaration of Independence claimed certain truths to be "self-evident", namely, "that all Men are created equal, that they are endowed by their Creator with certain unalienable rights, that among these are Life, Liberty, and the Pursuit of Happiness---."
The philosopher in us then asks: are these truths self-evident because they come from a Creator? Or, are they self-evident because humans have learned from experience that these particular values (life, liberty, pursuit of happiness) are necessary if we are to be civilized, compassionate, peaceful people?
If we abide by these truths only because a creator says so, where is the morality in that? On the other hand, what can be more moral than behaving in a way that promotes the right to life, liberty and the pursuit of happiness for all simply because it makes for the kind of nation/world in which we want to live?
The adage, to treat others the way you...