In its most general form, the moral argument is that:
One may ask why the required recognition and upholding of moral norms must be carried out by divine intelligence, as opposed to human intelligence. A. E. Taylor explains that the moral law holds everywhen and everywhere, whereas the human mind is limited in its comprehension and scope. Only a sovereign God could properly detect infringements of the moral law and apply sanctions. In his Letter concerning Toleration, John Locke contends that one of the few religious stances that the commonwealth cannot tolerate is atheism, for atheists have no motive to act upon their promises and oaths when doing so is against their self-interest.
Here, a transcendental fact is one that cannot be stated entirely in the language of the natural sciences, and that is true irrespective of human opinion. Theism provides the most intelligible explanation for such moral facts via the notion that rightness is one and the same property as the property of being commanded by God (wrongness consists in being forbidden by God).
In order for this argument to work, it should be shown that a non-theistic worldview cannot adequately account for transcendental normative facts. Historically, the burden of proof has been placed on the non-theist to demonstrate a naturalistic metaphysics for morals, as both proponents and opponents of the moral argument tend to agree that morality may be a phenomenon which shows that there is more to the real world than meets the physicalist's eye.
Critics suggest that this argument appeals to a divine command theory of ethics. Objections to divine command theories of ethics are numerous, most stemming from forms of the Euthyphro dilemma. Is an action good because God commanded it, or did God command it because it is good? The first horn would imply that what is good is arbitrary; God decides what is right and wrong in the same way that a government decides which side of the street cars should drive on. This seems unreasonable. The second horn could imply that God made his commands in accordance with transcendental facts that exist apart from God — exactly the types of facts that the theist is asking the non-theist to provide an account for. The argument is thus turned over on its head: the theist must account for the existence of these transcendental facts without invoking God. The non-theist can thus recognize the transcendentality of moral facts and yet still reject premise (2.3) on the basis that a theistic hypothesis still leaves transcendental moral facts unexplained.
Proponents of the argument maintain that the Euthyphro dilemma can be adequately resolved. Thomas Aquinas, for example, explains that God indeed commands something because it is good, but the reason it is good is that good is an essential part of God's nature.
Friedrich Nietzsche suggests elaborate explanations of how initially amoral social practices became artificially colored with moral significance. Some suggest that similar explanations of the phenomenon of morality are given through fields like Evolutionary dynamics (although some leading researchers on the evolution of altruism are Christian) (This isn't the place for this but I don't see where to write in the discussion page. Someone should move it into a better place, unless they want to spread nonsense and attack this with hatred, resent(i)ment and words like 'semantics' and 'parsing'. This statement about Nietzsche is diametrically upside down. He wrote at length about being an immoralist. As the etymology of 'moral' is custom, Nietzsche rejected all morals as having any merit or value at all as as an immoralist not an amoralist. So seeing as he wrote at length about how morals had no value specifically because they are only traditions as the etymology shows, this statement is diametrically upside down. This was a large part of his work and a central idea to his Revaluation of All Values. The choice of the odd sounding revaluation over the more familiar re-evaluation is purposeful, to infer that our current moral value system is totally without value and precludes any of our current moral values from making it through the revaluation. Nietzsche wrote somewhere (it is sloppy that I can't recall where) that if customs (morals) had value simply for being traditional, perhaps we should all still be sacrificing our first born sons. This was also his explanation as to why the future must never be a return to the past. The word believe as applied to Nietzsche is downright funny, as he ripped believing and faith to shreds quite often. But then again this ridiculous caption and sentence fits Nietzsche's description of our Christian value system as diametrically upside down. Same way Nietzsche is often called and noted as a Nazi philosopher with Wagner getting off the hook as 'just a musician.' So foolish and opposed to reality and actuality that it is diametrically opposed to nature. Nietzsche's biggest flaw was not being able to control a hatred towards Christian German Jew-haters, he even wrote he would like to shoot all Jew-haters in the head, while Wagner is an admitted and heavily published Jew-hater.)
Premises (3.1) and (3.2) reflect Immanuel Kant's belief that behaving morally should lead to happiness. Premise (3.3) tells us that "ought implies can". It cannot be true that we ought to seek an end if there is no chance of our attaining it. Premise (3.4) points to the fact that the world as it appears to us is governed by morally blind causes. These causes give no hope whatsoever that pursuit of moral virtue will lead to happiness. They do not even give hope that we can become morally virtuous. Agency is beset by weaknesses that make the attainment of virtue — in the absence of external aid — seem impossible. The being postulated in (3.5) has omniscience and omnipotence combined with perfect goodness. Thus it will ensure that the pursuit of a virtuous state is possible through external aid (as in grace) and will promise an immortality where the moral journey can be completed. It will also ensure that in the long run happiness will result from virtue. Its existence would mean that there is a perfect moral causality at work in the world.
Kant himself asserts that if the summum bonum cannot be attained, then the moral law that bids us to seek it "must be fantastic and directed to imaginary ends and must therefore in itself be false". Critics point out a certain type of circularity: Kant's argument presupposes that both the pursuit of moral virtue and the pursuit of happiness must be rational enterprises; however, this is precisely the sort of thing that may not be true in a non-theistic universe. Kant's conception of God arises as an attempt to harmonize these two conflicting goals, but critics assert that practical reason is not committed to the pursuit of two ends that apparently conflict.