In this page, I want to explain the concepts of Realism and Anti-Realism. A realist about something is someone who thinks that something exists. It really is that simple. So for example, a platonist is a realist when it comes to Universals. A nominalist is an anti-realist about Universals. You can be a realist about anything but philosophers typically talk about realism in terms of what exists outside our minds, those who think there is a world that exists outside our mind are realists in that sense. Those who do not, generally called idealists, think there is nothing that exists outside our minds. There are also moral realists who generally believe that there are moral facts, or there are moral properties. They believe that there are objective answers to moral questions. In a future post, I want to explain more about this branch of philosophy called metaethics.
Anti-realism is sometimes called nihilism. ("nihil" comes from "non-existence") This is not to be confused with a philosophy of life called nihilism that generally holds life to be meaningless or pointless. In our sense, those people are anti-realist about meaning in life. But typically when philosophers are talking about moral nihilism they are simply stating that moral facts do not exist. They are anti-realists about moral facts but are not necessarily nihilists in that more sad boi sense.