In this paper, I argue that legal forms constitute the available ways of thinking legally about relations between persons in light of how we conceive of persons in law. Legal forms, as normative ideals, do not of course determine what positive law there is nor do they even set out the particularities of the law we ought to have: for that, we have politics. With this view of legal forms in mind, I suggest a way to bridge the divide between those who think there is a distinctively legal way of reasoning about human relations (‘formalists’) and those who take themselves to reject the very possibility of distinctively legal reasoning (‘moralists’). I suggest that there is a common threshold question for moralists and formalists alike: how ought we to conceive of persons for the purposes of law and how could people so-conceived possibly relate? Both the moralist and the formalist produce legal forms in answering that question, forms that constrain the available ways of reasoning about legal relations. But we are not all formalists now: there remains substantial disagreement about how to answer the threshold question and how far we get by just answering that threshold question.