 The question remains as to which sorts of pleasures are of higher quality than others. Mill holds that pleasures “of the intellect, of the feelings and imagination, and of the moral sentiments” are amongst the higher pleasures (Utilitarianism, X: 211). But Mill’s doctrine need not be read as restrictively intellectualist. As well as pleasures of the mind, he holds that pleasures gained in activity are of a higher quality than those gained passively (Liberty, XVIII: 262; cf. Utilitarianism, X: 215). Ultimately, however, the quality of any given pleasure must itself be a substantive question, to be addressed by ongoing experimentation and comparison of the preferences of competent judges—those who have experienced, and appreciated, the sorts of pleasure being compared.