Hare’s purely formal criterion ruled out any restrictions on the content of morality and so ruled out any logical connection with human life. Like the Wittgenstein of the Tractatus, who placed value outside ‘the whole sphere of what happens’ (words she had heard Iris speak on the radio), Hare thought that there is nothing in reality to ground the objectivity of moral judgement. His philosophy, like Sartre’s, thus retained the formal structure of Kant’s categorical imperative, but with moral principles cut free of any transcendental background.
