Introduction | Types of Cognitivism
Cognitivism is the view that ethical sentences express propositions and can therefore be true or false (i.e. they are truth-apt). Thus, moral judgments are capable of being objectively true, because they describe some feature of the world.
A proposition in Epistemology is, roughly speaking, an assertion or a declarative sentence (as opposed to an interrogative, exclamatory or imperative sentence). Thus, an ethical statement which is a valid proposition (e.g. "Mary is a good person") is able to bear truth values, and one can say of it "that is true" or "that is false". Two people may disagree on its truth or falsity, but it has at least the capacity for truth.
The opposite view is that of Non-Cognitivism, the view that moral statements lack truth-value and do not assert propositions.
Moral Realist doctrines in Meta-Ethics, such as Ethical Naturalism and Ethical Non-Naturalism, implicitly assume that ethical statements are truth-apt propositions.
However, it is also possible for Moral Anti-Realist theories to accept that ethical sentences can be true or false, even if there are no natural, physical or in any way real entities or objects to make them true or false. Hilary Putnam (1926 - ) argues in his 2004 book "Ethics without Ontology" that ethical (and for that matter mathematical) sentences can be true and objective without there being any real world objects to make them so.
Thus, some Moral Anti-Realist theories like Ethical Subjectivism and the Error Theory variant of Moral Nihilism also assume Cognitivism.