Abstract
If harm is restricted to mean perceptible damage suffered by an agent against his wishes, so that his mere dislike with no evidence of injury is excluded, then Mill's liberty principle arguably is ‘one very simple principle’ as he claims. But even so, what of John Gray's charge that the liberty principle relies on a ‘radically defective’ notion of individuality or autonomy that is incompatible with every civil society's cultural and moral traditions? If he is correct about this, then Mill's principle lacks appeal even if it can be stated in a definite and coherent manner