The Power Of Guilt

Conscience is subjective, its existence and nature irrelevant to whether moral obligations exist and what those obligations are.  Moral feelings only tell the person experiencing them that they have moral feelings and what those feelings are like at a given moment.  All the same, it can be so powerful that some people, despite having never rationalistically or even directly but irrationally thought about moral concepts, will feel guilt strongly enough that they will avoid certain actions even if no one would ever see them and object.  Conscience could deter certain people from doing things that are obligatory, permissible, or evil simply because guilt can be powerful enough to torment people regardless of their worldview.

No one has to be a theist or an adherent of any particular religion to feel a certain way about an act, thought, or concept.  Of course, how anyone feels about something proves only that they feel that way, and whether nihilism or some kind of theistic moral realism is true--for these are the only two logically possible options--does not depend on anyone's inability to prove or disprove them.  If moral obligations exist, they are not a matter of perception or preference; if no moral obligations exist, their nonexistence is not a matter of perception or preference.  The only uses of conscience are revealing to people part of themselves, potentially prompting thought about moral philosophy, and deterring a person from various lifestyles in the meantime.

Anyone who does not look past immediate perceptions and assumptions will never recognize any of these knowable truths, including the truth that both theistic nihilism and theistic moral realism are logically possible (there simply is an uncaused cause, so that part is not unknowable).  Just getting to even this point requires an intentional, consistent alignment with reason, as conscience alone never reveals anything more than itself.  Moral feelings and not moral obligations or the concept of moral obligations.  They are subjective, malleable moral emotions that can exist without any moral obligations beyond them, and vice versa.

Even if morality does not exist, there would still be objective logical truths about what would follow from a given moral obligation, which moral systems are self-contradictory and thus false by default, and why morality does not exist.  The truth at hand is just the fact that no matter what most people who have a conscience believe--and not everyone is necessarily born with one or does not have theirs disappear--it is likely that they will act as their conscience compels them to simply because of how strong its impulses are.  No matter how irrational, hypocritical, unpopular, hated, or misunderstood they might be, many people will let their conscience guide them when it is intense enough.

Theists, atheists, rationalists, irrationalists (with everyone being an irrationalist to the extent they cling to fallacies, assumptions, and preferences instead of logical truths), and others tend to have some sort of conscience.  What their moral feelings can differ enormously, and the rationality or irrationality of their true philosophical stances on conscience and morality can likewise differ, but conscience itself, for those who have it, can produce very strong reactions, motivations, and desires.  It is absolutely vital that anyone who sheds whatever assumptions they had before rationalism shed any assumptions about conscience, such as the idea that it is moral obligation itself or that it proves moral obligation exists (or the myth that its subjectivity proves objective morality does not exist).  Such a powerful kind of feeling will drive someone to major errors if not evaluated rationalistically.