The first three chapters of this book contain a clear explanation of some key concepts in the philosophy of Nicolaus Cusanus. For example: the concept of the human being as a gathering being, the meaning of the concept of conjectura and of the principle of docta ignorantia. Other subjects discussed are the relation between the signum and significatum, the characterisation of human knowing as a kind of measuring and the inevitable commitment of the thinking and knowing human being to truth as an unattainable but nevertheless dynamic force. In these chapters the author demonstrates a profound knowledge of the thought of Cusanus, and provides a clear exposition of some of the most fascinating aspects of Cusanus’ philosophy. Bocken places this philosophy in the context of the fifteenth century and the Renaissance, a historical period in which the traditional medieval ordo-thinking broke down under the growing influence of nominalism. In this period, the attention of intellectual Europe was directed to the human being as the artistic and intellectual creator of his own world. Cusanus’ concept of man as a microcosm and a second god is placed in this context.

Another issue, which is discussed in the fourth and fifth chapter of the book, is tolerance. Because he was intensely involved in the struggle between Christians and Muslims for Constantinople (Istanbul), the question of tolerance played a central role in cardinal Cusanus’ life. The author shows that in the philosophy of Cusanus there is room for the phenomenon of the pluriformity of various religions without resorting to a relativist theory of truth, a relativism which seems characteristic for a Modern point of view concerning the question of tolerance. In this respect the author confronts Cusanus’ philosophy with that of Kant and Hobbes. He argues that Hobbes and Kant address the problem of tolerance in the formal political context of the state of nature and the social contract, and thereby abstract it too much from the truth-commitment of the subjects. Thus, the question of tolerance is treated as a formal and empty political entity. This modern view of the Enlightenment results in an artificial separation of the private and public domain, religion being placed in the private domain. The author argues that in line with Cusanus’ thought, one can never abstract oneself from an inevitable commitment to truth, even if the truth can never be attained and even if there will always be a pluriformity and diversity of life-forms and conjectures.

In the sixth chapter, the author confronts Cusanus’ thought with Descartes’ idea of God. He argues that the idea of God plays a central role in the constitution of the autonomy of the cogito in the third meditation of Descartes Meditationes. In this respect there is, according to the author, some resemblance with the idea of God in Cusanus. Nevertheless, the difference between the outer and the inner world is not completely bridged by Descartes’ idea of God, while in Cusanus’ thinking this difference is in a certain way included in the idea of God.

In the last chapter the author confronts Cusanus’ idea of conjecture with Karl Jaspers’ concept of chiffre. Although striking similarities between these two concepts exist, there are important differences as well. For instance, whereas in the line of Cusanus’ reasoning the starting-points and main concepts of modern science must be treated and discussed as conjectures of the human being, these concepts are not profoundly discussed, but are mainly taken for granted by Jaspers.

In the Epilogue, the author states the fruitfulness of Cusanus’ philosophy with respect to modern debates concerning truth and tolerance, war and peace, multiculturality and religious pluriformity. The main reason for this fruitfulness is that in Cusanus’ thought the authentic truth-commitment of every human being as a conjecture-creating entity is not sacrificed in the name of a liberal society, in which there is a strong tendency to abstract systematically from this essential characteristic of the human being and its religious and other life-forms.

This book offers both a clear introduction to some of the central themes of Cusanus’ philosophy, covering most of his works, and a fruitful confrontation of this philosophy with the thought of other philosophers such as Descartes, Hobbes, and Jaspers. In addition, it offers an interesting perspective on various issues of debate in modern time.