Sure they do. As much as you're obliged to carry out the trash. It's a contract between people. They exist objectively every time two people interact with each other, just like any other contract in this world.
Because, and that might blow your mind, the natural state of a human being is to not have a concept of a God. And believe it or not, those cultures are still moral as you and I.
Jeez.
rumborak
This is mere Atheistic Moral Platonism, that objective moral values exist without any sort of foundation.
There are at least three distinct problems with Moral Platonism, though.
1.) It is unintelligible.
What does it man to say, for example, that the moral value "justice" just exists? It's understandable to say that
some person is just, but it's astonishing to posit that in the absence of any people, justice itself exists. Moral values are properties of persons and its problematic to comprehend how justice can exist merely as an abstraction.
2.) It provides no basis for moral duties.
For the sake of the argument, let's suppose moral values simply exist. How does that result in any moral obligations for me? Why would I have a moral duty to, for example, be charitable? What or who lays such an obligation upon me? In this worldview, too, moral vices like hatred, lethargy, selfishness, greed, etc, presumably also exist on their own as abstractions. So why align ourselves with one set of these abstractly existing entities and not others?
3.) It's cosmically improbable that an blind evolutionary process would discharge exactly the sort of creatures who correspond to the abstractly existing realm of moral values?
It's almost as if the moral realm
knew we were coming. It's fantastically more probable to posit that both the natural realm and the moral realm are under the supremacy of a God who provided us both the moral law and the laws of nature than to believe that these two independent realms just so happened to complement each other so fully.