Eberhard Schockenhoff relates an exceptional discussion of the concept of natural law as it applies to a modern world of moral relativism. Schockenhoff draws on a vast collection of philosophical and theological thinkers to recover a theory modern moral theology has shrugged off as a 'historic burden.' Schockenhoff offers two possible models for the natural law; the first rests on a foundation of the philosophical anthropology of Max Scheler and is compatible for serving as a framework for an obligatory 'minimum code' of secular legalism. The second maintains the same structure as the first and augments it with the theological anthropology of the Christian tradition, forming here a non-obligatory 'maximum code' of ethical moralism. The same ultimate principle resides in each system: the human dignity that is demanded by the essence of each human being. In the legalistic understanding of the natural law, one must observe the minimum code of respect for human dignity in one's ethical action. In the moralistic understanding of the natural law, one must observe the maximum code of Christian love (agape) in one's ethical attitude for all persons. Until the majority of moral agents in socio-historic framework realize the maximum code, justice must serve as the modality through which agape is administered (Aquinas).
Schockenhoff realizes that the tradition of natural law is problematic and has been abandoned by many moral theologians. He approaches the subject from several angles and responds to many classical objections. Although Schockenhoff offers no concise history of natural law thinking in a developmental chronology, one is able to grasp the key problem points that Schockenhoff relates in survey fashion. From his negative critique of classical objections Schockenhoff gradually integrates a positive argument that counters each problematic area. He begins by addressing the perennial chief concern: that of justification for a universal natural law in an era where ethical relativism has become standardized. There are several issues conjoined in the problem of justification: objections of ambiguity, logical flaws and the empirical facts of historic and cultural relativism.
Drawing on the philosophical concept of historicism as considered by several theologians, philosophers of hermeneutics and of existentialism, Schockenhoff demonstrates, with some help from the thought of phenomenological ethicist Max Scheler, how mutually exclusive historic and cultural ethical systems share a common anthropological foundation. Scheler, borrowing the 'eidetic reduction' of phenomenologist Edmund Husserl (a methodological technique of 'bracketing' in phenomenology that Schockenhoff refers to as a 'transcendental reduction') concludes in his thought that the individual essence (eidos) of each human person contains incalculable ethical value. From this standpoint of philosophical anthropology, the value of the human person can be demonstrated as universal, transcending yet underlying all relative historic and cultural forms in various approximations. The relative approximations of each historic-cultural ethical system to a natural law founded upon human dignity are measurable by a sliding scale, a scale by which some approximations are closer to the natural law than others. In this model the natural law is never completely absent from a system unless it attempts to ground itself in pure legal positivism alone. In other words, in any historic-cultural ethical system that is reasoned by some recourse to a non-positivistic value (i.e. one that doesn't reduce to a 'brute ethics' of enforcement), one will find some approximation of the natural law as Schockenhoff understands it.
From here Schockenhoff appropriates the philosophy of 'practical reason' as understood by St. Thomas Aquinas as a modality by which the essence of each human being can be understood as a representation of the natural law as founded upon 'human dignity.' The universal of 'human dignity' is only an appropriate ethical foundation when applied to a particular human being. This foundation is compliant not only with numerous philosophical ethical theories (including Kantian deontology), but also with many pre-Christian codes of ethical conduct, including the Decalogue itself. From this perspective Schockenhoff is able to defend another 'antiquated' concept of moral theology, that of 'intrinsic evil.' By Scheler's foundation in philosophical anthropology, the 'intrinsic evil' can now be understood as any action that violates human dignity (e.g. torture or rape). This anthropological foundation of the natural law ensures a minimum code of action enforceable by any society governed by the rule of law.
The natural law also contains a subsequent dimension, inferred from Christian revelation, which must be realized by those aspiring to a code of conduct higher than that of mere legalism. Maintaining a sharp differentiation between the legal and moral realms, Schockenhoff goes on to demonstrate how his understanding of a natural law founded upon human dignity integrates with Christian agape. The legal regulates action, whereas the moral regulates attitude. In this sense the same personal essence of each human being that demands legalistic respect of human dignity also is the object of agape, i.e. Christian love and compassion.
Schockenhoff's work is challenging: his style of writing is of high caliber, and may be demanding for the novice reader. Those schooled in the analytic tradition of philosophy may find his argumentation not as strictly formal or easy to follow as might be desired. Further, the book requires some familiarity with terminology from philosophical ethics and moral theology. However, Schockenhoff's work does not require antecedent study of any of the thinkers mentioned here (Scheler, Husserl, Aquinas, etc.), as he goes into great detail explaining which concepts he is borrowing and what purpose they are meant to serve in his own thought. The only possible drawback to the work, for North American readers, is that many of Schockenhoff's references and citations are derived from contemporary German thinkers and academics that may be unfamiliar. However, the key thinkers Schockenhoff examines should be well-known names to any professional or student moderately familiar with Continental philosophy. This is a high quality work, providing both a wide overview of the concerns of natural law and offering a respectable solution worth further consideration. Schockenhoff's work is highly recommended.