Melissa Moschella, who teaches the practice of philosophy at the University of Notre Dame, Indiana, USA, has given us an exceptionally useful exposition of the fundamentals of the ‘new natural law theory’ of moral philosophy in the tradition of Aristotle and St Thomas Aquinas. With crisp clarity she progresses logically from the ‘basic human goods’ which form the first principles of ethics, to those moral principles which can be put to work to guide us in policy-making and the taking of personal moral decisions. She applies such moral principles in the social dimension and in the political dimension of human flourishing. There is a final chapter, quite slender, where she speaks from faith to faith, rather than as the reasoning philosopher, invoking the Kingdom of God as the promised reality towards which ethics strives. While for the new natural law school, ethics does not require a metaphysical or theological basis, as it does for Aquinas, and so is universally valid and applicable, which is an advantage if it works, Moschella does see the ultimate connection between ethics and theology and so maintains her link with Aquinas. For him, the natural law is ‘the rational creature’s participation of the eternal law’ which reflects the mind of God and this surely is the key to the whole edifice of ethics.

The ‘new natural law theory’, as it has come to be known, was pioneered by the (mainly) Roman Catholic philosophers Germain Grisez, Joseph Boyle, John Finnis, Robert P George and several others (with a not uncritical ally in Jean Porter’s independent recovery of Aquinas on natural law), from the 1960s and continues to be developed and refined to the present day (of which this work is one example). The ‘new natural law theory’ is distinguished from what we might call ‘classical’ or ‘received’ natural law theory by the detachment of its method from a priori metaphysical or theological appeals to the created order as it is (human nature and the natural world), which some attribute to Aquinas, although more likely it belongs to his later textbook interpreters. Instead, the new natural law theory starts from empirical or self-evident basic human goods such as existence, knowledge, aesthetic experience, friendship, marriage and religion, which are both intelligible and intrinsic and constitute the springs of human action. It holds that, by the application of practical reasoning (phronesis), we can deduce moral principles from these basic goods and so learn how we should live a life of practical virtue. Its advantages include: affirming the connection between morality and human flourishing (which Aristotle called eudaimonia and the author refines as ‘integral human fulfilment’); insisting on certain moral absolutes such as the prohibition of lying, rape and murder; and the vital part played in the moral life by the habitual development over time of individual moral character (habitus).

Aquinas himself also affirms the basic human goods as the constituents of the good life; they are intrinsically choice-worthy, motivating our action. Taken together, they comprise the common good (bonum commune). But in Aquinas the common good points to, participates in, and leads up to the ultimate Good, the summum bonum, which is God. This is crucially where Aquinas exceeds Aristotle who leaves ethical principles rather hanging in the air. More could have been made in this book of ‘the Good’ when we are talking about ‘goods’. Plato, as well as Aristotle, has something to offer. Moreover, human flourishing cannot come about in isolation, but only in relationship and in community. So the concept of ‘basic human goods’ points to the concept of ‘the common good’, a concatenation of good things to be held in common and which can only be achieved in common by many wills being united in pursuit of a shared goal.

So the new natural law theory is also helpfully applied here to the political sphere where the goal, aim and ultimate horizon of action should always be the common good. Political authority is both necessary and constrained. It serves to coordinate the aspirations and activities of the many ‘sub-political’ units within what I would call ‘civil society’ (although I think that expression is not used here), which is the vast sphere of social, cultural and institutional entities, between the family and the state, which make up the fabric of a nation’s life. In that sense, political authority serves the components of society by providing an over-arching framework of national and societal security and public provision of services for pursuit of the common good.

The principle of subsidiarity governs (or should govern) the governors. The higher serves the lower, not the other way round. The state should affirm the agency of the sub-political communities of civil society, which each have their proper spheres of competence, not try to absorb that agency into itself, for it is by such means that we constitute ourselves as persons in community. As Aquinas insisted, legislators should always legislate for the common good. In the context of democratic liberalism, this means that governments cannot feign moral neutrality or profess not to be concerned about the moral virtue of its citizens. It must be guided by natural law, whether it acknowledges it or not. Natural law is our defence against the dictatorship of legal positivism. Defenders of natural law do not claim that its contents can be easily specified, but it brings to bear the principles of justice, prudence and charity on laws which are an abuse of legislative power. The fifteenth-century Conciliarists invoked natural law in defence of the common good of the church (status ecclesiae) which had been fractured by the great papal schism of the West (1378–1417). The Reformers (Luther, Melanchthon, Bucer, Calvin; later Hooker) invoked it against oppressive papal laws and abuses that required reform and to guide the reconstruction of the Protestant commonwealth. Natural law and its companion, the concept of the common good, are still our guiding stars in the firmament of Christian ethics.

There is a useful apparatus to assist the reader to follow the argument of the book and to guide further reading.