Moral nihilism (also known as error theory) is the
meta-ethical view that there are no moral facts, where facts are (roughly) true propositions. Moral nihilists hold that there are no objective moral facts---that nothing is morally good, bad, wrong, right, etc.---because there are no moral truths. For example, an error theorist would say that murder is not wrong, but it's not right either. Some prominent, recent moral nihilists (or error theorists) are
J. L. Mackie (1977) and Richard Joyce (2001).
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Moral skepticism is the
meta-ethical view that no one has any moral knowledge. Some moral skeptics would even make the stronger modal claim that no one can have any moral knowledge. In either case, moral skepticism is particularly opposed to
moral realism: the view that there are objective mind-independent moral truths.
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