Clear and distinct perception is the centrepiece of Descartes’s philosophy — it is the source of all certainty — but what does he mean by ‘clear’ and ‘distinct’? According to the prevailing approach, what it means for a perception to be clear is that its content has a certain objective property, like truth. I argue instead that clarity is at least partly a subjective, phenomenal quality whereby a content is presented as true to the perceiving subject. Clarity comes in degrees. (...) Any weak degree of clarity, available to the senses, can be merely subjective, since what it presents as true may not actually be true. But complete clarity, available to intellectual perception, has an objective dimension, since what it presents as true is always some truth, some bit of reality. Further, I argue that the other perceptual qualities that Descartes identifies — obscurity, confusion, and distinctness — are all defined in terms of clarity. Of particular note is the fact that distinctness is not a positive feature to be added to clarity: a distinct perception is just a completely clear perception. (shrink)

In his Principles of Philosophy, Descartes says, Finally, it is so manifest that we possess a free will, capable of giving or withholding its assent, that this truth must be reckoned among the first and most common notions which are born with us.

Book review of John Schuster: Descartes-agonistes: Physico-mathematics, method and corpuscular-mechanism 1618-33. (Studies in History and Philosophy of Science, Volume 27.) Dordrecht: Springer, 2013, xix + 631pp. Descartes-Agonistes is the magnum opus of John Schuster, formerly of the University of New South Wales, honorary fellow at the University of Sydney. Its roots go back to the dissertation he wrote 35 years ago under Thomas Kuhn at Princeton University. As Schuster correctly remarks, some regard his dissertation as an underground classic. I count (...) myself among them: Schuster’s work has been directional in my work on the history of early modern science. Schuster himself prefers to regard his dissertation as ‘a vestige’ of a history of science of the 1970s that he has since gone beyond. In the 1980s, he elaborated and published on some central insights in a series of seminal articles, but his work on Descartes really got into its stride again around the turn of the millennium (Schuster 1980, 1990; Gaukroger et al. 2000). This book is the acme of this work, and grand it is: clocking 600 pages (excluding appendices) it extends, deepens and reinforces his analysis of Descartes into a dense and .. (shrink)

This paper examines the ethical and religious dimensions of mathematical practice in the early modern era by offering an interpretation of Antoine Arnauld and Pierre Nicole’s Nouveaux éléments de géométrie. According to these important figures of seventeenth-century French philosophy and theology, mathematics could achieve extra-mathematical or non-mathematical goals; that is, mathematics could foster practices of moral self-improvement, deepen the mathematician’s piety and cultivate epistemic virtues. The Nouveaux éléments de géométrie, which I contend offers the most robust account of the virtues (...) cultivated by mathematics in the period, was envisaged by its authors to cultivate moral, Christian and epistemic virtues that could serve in the fulfilment of moral and Christian obligations. In this paper, I set out the goals of mathematical inquiry for the Port-Royalists and describe the specific virtues they believed a revised edition of the Elements of Euclid could foster. I show that Arnauld and Nicole believed that an acquaintance with mathematics could render a student of Euclid more just, truth-loving, attentive and humble, and better able to discern truth from falsity. (shrink)

Additional theorizing about mathematical practice is needed in order to ground appeals to truly useful notions of the virtues in mathematics. This paper aims to contribute to this theorizing, first, by characterizing mathematical practice as being epistemic and “objectual” in the sense of Knorr Cetina The practice turn in contemporary theory, Routledge, London, 2001). Then, it elaborates a MacIntyrean framework for extracting conceptions of the virtues related to mathematical practice so understood. Finally, it makes the case that Wittgenstein’s methodology for (...) examining mathematics and its practice is the most appropriate one to use for the actual investigation of mathematical practice within this MacIntyrean framework. At each stage of thinking through mathematical practice by these means, places where new virtue-theoretic questions are opened up for investigation are noted and briefly explored. (shrink)

The mathematical nature of modern science is an outcome of a contingent historical process, whose most critical stages occurred in the seventeenth century. ‘The mathematization of nature’ (Koyré 1957 , From the closed world to the infinite universe , 5) is commonly hailed as the great achievement of the ‘scientific revolution’, but for the agents affecting this development it was not a clear insight into the structure of the universe or into the proper way of studying it. Rather, it was (...) a deliberate project of great intellectual promise, but fraught with excruciating technical challenges and unsettling epistemological conundrums. These required a radical change in the relations between mathematics, order and physical phenomena and the development of new practices of tracing and analyzing motion. This essay presents a series of discrete moments in this process. For mediaeval and Renaissance philosophers, mathematicians and painters, physical motion was the paradigm of change, hence of disorder, and ipso facto available to mathematical analysis only as idealized abstraction. Kepler and Galileo boldly reverted the traditional presumptions: for them, mathematical harmonies were embedded in creation; motion was the carrier of order; and the objects of mathematics were mathematical curves drawn by nature itself. Mathematics could thus be assigned an explanatory role in natural philosophy, capturing a new metaphysical entity: pure motion. Successive generations of natural philosophers from Descartes to Huygens and Hooke gradually relegated the need to legitimize the application of mathematics to natural phenomena and the blurring of natural and artificial this application relied on. Newton finally erased the distinction between nature’s and artificial mathematics altogether, equating all of geometry with mechanical practice. (shrink)