Keywords

Christian Wolff (1679–1754) is one of the leading figures in eighteenth-century Western thought, usually counted as the most eminent German thinker between Leibniz and Kant. Wolff’s works found a wide audience among European philosophers and scientists from numerous fields and his fame attracted many students from different countries to come to Germany.Footnote 1 Wolff became professor in Halle and Marburg, and later a member of the Royal Society in London and the academies of Berlin, Halle, Paris, St. Petersburg, Stockholm, and Bologna. In recognition of his service in modernizing German academic philosophy, he was called praeceptor Germaniae (educator of the German nation) and, in 1745, received the title of Imperial Baron (Reichsfreiherr) of the Holy Roman Empire.Footnote 2

Wolff was a systematic thinker and accordingly it is important to consider his philosophical views from the perspective of the whole. His work covered not only logic, metaphysics, and ethics, but also such fields as political theory, natural law, and law of peoples, mathematics, mechanics, or economics. At the same time, he tried to order and articulate them in a new way as a system.Footnote 3 Wolff invented new philosophical and scientific disciplines, although he would not draw such a distinction himself. After Wolff, it became commonplace, at least in the German tradition, to conceive of a philosophical system in terms of a general metaphysics, or ontology, and a special metaphysics―comprising cosmology, psychology, and theology―preceded by logic and followed by ethics, politics, and other practical disciplines.Footnote 4

In the last decades, the publication of Wolff’s Gesammelte Werke by Jean École and his collaborators has aroused new interest in his ideas, which has led to interesting and important reappraisals in the scholarly literature. For example, it has become clear that Wolff’s philosophical program was neither a mere rephrasing of Leibniz’s ideas nor just a preparation for Kant’s critical philosophy. On the contrary, there is a growing understanding that Wolff was an original thinker, who has to be understood in his own terms. However, notwithstanding the merits of such reevaluations, many aspects of his thought remain open to new investigations and deserve further analysis and discussion.

Reappraising Wolff’s philosophy, however, goes beyond a purely historical interest. Wolff’s philosophical system also matters because it poses challenges that are still alive today, such as the relationship between philosophy and psychology. In particular, the meaning, scope, and impact of Wolff’s psychological program have not received sufficient attention in the literature. Although he did not coin the term psychologia,Footnote 5 Wolff was the first to give psychology a new status: (1) by establishing it as a proper science or discipline among the special philosophical sciences (next to ontology, theology, cosmology, moral philosophy, economics, etc.), (2) by assigning to it a key role in the foundation of moral or practical philosophy, and (3) by inaugurating a division of psychological knowledge into two main branches—psychologia empirica and psychologia rationalis —, thereby setting a new agenda for debates that ranged from enthusiastic acceptance to fervent criticism.Footnote 6 Finally, one should not forget that the so-called emergence of scientific psychology in the nineteenth century cannot be dissociated from the development of a new psychological culture in the eighteenth century, largely based on Wolff’s legacy.

Considering all those aspects, a new volume on Wolff’s psychological program may help to consolidate his contributions not only to philosophy, but also to the human sciences in general. The last collection of essays dedicated to Wolff’s psychology was published in 2007 (Marcolungo, 2007), and the last monograph appeared in 2011 (Mei, 2011). Since then, only isolated articles and book chapters have been published (e.g., Chance, 2018; Dyck, 2014; Rumore, 2018; Goubet, 2018). The present volume offers, for the first time in English, a comprehensive anthology of essays by an international group of leading scholars on Christian Wolff’s psychology and its historical impact.Footnote 7 It explores Wolff’s psychology comprehensively in its various aspects. Moreover, it closes a linguistic gap in Wolff scholarship: most publications on Wolff and his psychological program have appeared in German, French, Italian, or Spanish, but so far there is not a single book dedicated to Wolff’s psychology in English.

Our principal goal is to offer a broad account of Wolff’s psychological program and its impacts that may contribute to the disciplinary fields of historiography, philosophy, and psychology, not to mention Wolff scholarship. To do this, we have divided the contributions into two parts. Part I covers the scope and contents of Wolff’s psychology, both in its internal structure and in its relation to other parts of his philosophical system, such as logic, ontology, cosmology, theology, aesthetics, and practical philosophy. Part II deals with the reception and impact of Wolff’s psychology, starting with his early disciples, then moving on to Kant and others, until reaching the nineteenth century with Hegel and Wundt.

As an antechamber to both parts, Ursula Goldenbaum offers a fresh and illuminating account of the historical context underlying the development of Wolff’s psychology. She uses a wide range of primary sources to highlight biographical, religious, political, and institutional aspects that help us understand the formulation and the fate of Wolff’s psychological program.

Beginning Part I, Thiago Pereira and Saulo Araujo explore, in Chap. 3, the origins of Wolff’s psychology in his German writings. Bringing together historical and philosophical analysis, they present content and context of its first exposition in the Deutsche Metaphysik (Wolff, 1720)Footnote 8 and its further development and clarification in the Anmerckungen (Wolff, 1724) and the Ausführliche Nachricht (Wolff, 1726).

Chapters 4 and 5 analyze in closer detail the specific contents of both psychological disciplines―empirical and rational psychology. Ferdinando Marcolungo explores the relationship between reason and experience in empirical psychology, whereas Corey Dyck unveils the meaning of Wolff’s rational psychology, offering a critical response to current interpretations of Wolff’s rationalism.

Manuela Mei, in Chap. 6, investigates one of the many innovations of Wolff’s empirical psychology, namely, his conception of psychometria. She shows in which sense Wolff believed in the possibility of a quantitative knowledge of the human mind, and compares his understanding of psychometrics with that of Robert Greene (1678–1730).

Next (Chapter 7), Falk Wunderlich analyzes the mind-body problem in connection with Wolff’s psychology. More specifically, he deals with some of its metaphysical aspects, such as Wolff’s understanding of Leibniz’s monadology and the doctrine of pre-established harmony.

In Chap. 8, Matteo Favaretti Camposampiero examines the connection between Wolff’s logical and psychological doctrines. He argues that a psychologistic reading of Wolff is one-sided and obscures the foundational role logic plays with respect to psychology.

Márcio Suzuki and Mario Spezzapria, in Chap. 9, delve into the relationship between aesthetics and empirical psychology. They claim that Wolff’s remarks on representation as a composition give the concept of image a new status, which will have important aesthetic consequences.

The relationship between psychology and practical philosophy is explored by Dieter Hüning in Chap. 10. He examines the psychological assumptions underlying Wolff’s concept of natural obligation as well as its implications for debates surrounding the concept of natural law and the will.

In the last chapter of Part I, Jean-François Goubet discusses the relationship between psychology and the other metaphysical disciplines: ontology, cosmology, and theology. He illustrates their important connection by analysing Wolff’s conception of pleasure.

Part II, then, addresses the legacy of Wolff’s psychology. In Chap. 12, Sonia Carboncini shows how Wolff’s disciples and followers further developed and disseminated his psychological program within and beyond the German borders.

In Chap. 13, Stefan Heßbrüggen-Walter discusses the reception and the debates associated with Wolff’s conception of the faculties of the soul. More specifically, he explores the realist interpretation of the faculties by authors such as Alexander Gottlieb Baumgarten (1714–1762), Johann Christoph Gottsched (1700–1766), Georg Friedrich Meier (1718–1777), or Johann Georg Sulzer (1710–1779).

Andreas Rydberg offers, in Chap. 14, a new look into the beginnings of experimental psychology in the eighteenth century. He traces the idea of psychological experiments back to Wolff and, in the aftermath, to three different discourses that developed in that context, namely, the experimental-philosophical, the iatromechanical, and the ethical-metaphysical.

Next, Michael Bennett McNulty (Chap. 15) illustrates the reception of Wolff’s psychology by Immanuel Kant (1724–1804). In particular, he shows that Kant not only rejected the metaphysical aspects of rational psychology but also criticized the empirical side of Wolff’s program.

In Chap. 16, Werner Euler discusses the reception of Wolff’s psychology by Hegel. More specifically, he shows that Hegel criticized Wolff’s rational psychology for being an abstract metaphysics that is unable to apprehend the essence of its object, namely, spirit. Instead of presenting yet another theory of the mind-body relation, Hegel proposed a wholly new way of approaching the study of spirit.

In the last chapter, Saulo Araujo and Thiago Pereira explore the reception of Wolff in nineteenth-century German psychology. More specifically, they show how Wilhelm Wundt (1832–1920) adopted and interpreted Wolff’s psychology by way of establishing his own conception of a psychological science, though they also point out a number of important respects in which Wundt appears to have misunderstood Wolff.

Together, these chapters show that Wolff’s psychological ideas are historically and philosophically more significant and interesting than conventional wisdom admits, but also that they are subject to misinterpretation. In general, Wolff’s psychology remains a challenge to historians, philosophers, and psychologists. We hope this volume will contribute to bring Wolff’s psychology to a wider audience.

Finally, we wish to note that, despite our comprehensive approach to Wolff’s psychology, important facets and aspects have not been addressed here. For instance, the relationship between empirical psychology and practical philosophy involves many other factors. In addition, it would be interesting to show how the idea of rational psychology was carried forth in the eighteenth century by authors such as Moses Mendelssohn (1729–1786) and Johann Nicolas Tetens (1736–1807). Wolff’s reception in the nineteenth century also deserves more attention. After all, it was not only Hegel and Wundt that discussed and commented Wolff’s psychology. This is of course just to say that a single volume cannot exhaust the richness, complexity, and legacy of Wolff’s contributions to psychology, but we hope that the present volume will serve as a foundation for further research in these and other directions, in the future.