If God is dead, then everything is permitted, worried Dostoevsky. Without a realm of moral facts independent of our minds, objective moral truth seemed impossible. Yet, argues Justin Clarke-Doane, moral anti-realism is perfectly compatible with objective moral truth. Conversely, if we insist on realism about mathematics – the idea that our mathematics tracks a reality outside of our minds – then we must give up on the idea that mathematical claims are objectively true. Realism and objectivity, far from always going together, seem here to be in tension.

Realism and objectivity

To what extent are the subjects of our thought and talk real? This is the question of realism. Realism about a subject says that there are facts about it, and these facts hold independently of our beliefs. For example, many of us are realists about mathematics. We believe that there are facts about numbers, sets, and tensors, and these facts do not depend on us. Realism contrasts with constructivism, according to which the facts about a given subject do depend on the minds of enquirers. Many of us are constructivists about aesthetics, for instance.

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Philosophers have widely associated, and even identified, realism and objectivity. But this is a mistake. As we’ll see, realism and objectivity are in tension in domains like mathematics and morality.

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What is the relationship between realism and objectivity? Objectivity about a subject opposes relativism, the idea that there are only relative facts about the subject. Philosophers have widely associated, and even identified, realism and objectivity. But this is a mistake. As we’ll see, realism and objectivity are in tension in domains like mathematics and morality.

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