Gaukroger ends his introduction with the words: "An intellectual biography forces one to think in very specific terms, hopefully yielding a kind of understanding which historians of philosophy of science have missed". This point of view marks one of the strengths as well as one of the weaknesses of this work on Descartes.
This intellectual biography offers a detailed exposition on the intellectual development and evolution of thought of René Descartes. The book strictly follows the chronology of events in Descartes' intellectual life and starts with his early childhood and education at La Flèche. This chapter excels in providing insight in 17th-century Jesuit education systems and the influence they had on Descartes' methodology and fields of study. Chapter 3 focuses on Descartes' apprenticeship with Isaac Beeckman in Holland and the decisive influence the latter's corpuscalarian thinking had on the natural philosophy of Descartes. Starting from this corpuscalar theory, Descartes developed an arithmetical account of consonance in music and alternative explanations for the kinematics of falling bodies and the problems of hydrostatics. During this period, Descartes discovered the proportional compass (mesolabe), which led him to the ambitious idea of a general theory of mathematics. In chapter 4 Gaukroger puts forward the interesting thesis that Descartes' search for a general theory of "method" was partly influenced by the contact he had with the Rosicrucians in Germany and he was to share in something like the generality and the delusions of grandeur of their vision of a universal language, generating all truths from basic premises. Later, on returning to France, Descartes had to defend himself against charges of being a Rosicrucian, which was considered to be a political threat. During these libertine Paris years, covered in chapter 5, Descartes pursued his interests in natural philosophy and mathematics in close contact with Mersenne, Mydorge and others. During these three years Descartes discovered the law of refraction in optics, lays the foundation of analytic geometry by the arithmetization of geometrical problems and develops a theory of perceptual cognition. In 1629 Descartes moved to Holland and stayed there for almost 20 years. During these years, discussed in chapters 6 to 8, Descartes worked on several publications: Le Monde, his most important work on natural philosophy, L'Homme, an exposition of a mechanist physiology, Geometry, a first account of analytic geometry, and Discourse of Method, a metaphysical foundation of his thinking, which established him as the best known philosopher of the 17th century. Gaukroger meticulously traces origins and dates of the respective chapters in these books and points them to specific periods of Descartes' intellectual life. Descartes' attempts to systematisation, his later publications and the critics these evoked, are discussed in the final chapters.
Gaukroger establishes a rationale for Descartes' intellectual pursuits both in terms of his motivations and in terms of the specific cultural context in which these motivations bear fruit and thus fulfils his goals for writing this intellectual biography. The book will appeal to students of philosophy and history of science that are already familiar with Descartes. A close reading of this book will guard them from the homogenization from thought in previous writing on Descartes and offer them a better understanding of the genesis of and significant changes in his doctrines. However, this biography fails in both precisely identifying many of the mathematical problems studied by Descartes, and in placing them within their correct historical context. A particular example is Descartes' solution for the problem of a depressed quartic equation, cited in every textbook on the history of mathematics. Gaukroger fails to provide an appreciation of the problem, to discuss previous solutions given by Viète and 16th-century Italian mathematicians and to explain Descartes' solution. Offering a better understanding of Descartes' study fields may indeed not have been Gaukroger's ambition but I am convinced that many readers will be missing this aspect in a scholarly biography of one of the most inspiring natural philosophers of the 17th century.