The importance accorded to Descartes by the country of his birth can today be gauged from the official address of his birthplace: Maison de Descartes, Rue Descartes, Descartes (Cottingham p20 fn11). He was born in 1596 to relatively wealthy parents on the fringes of the nobility and attended the Jesuit college in La Flèche. In 1618 he enlisted in the Dutch army as a gentleman soldier, and the following year joined the army of Maximilian of Bavaria. During his military service in the Thirty Years’ War he saw no fighting, and spent most of his time solving engineering problems.
In November 1619, while shut away in a small stove-heated room in Germany, he had a philosophical revelation that determined the direction of his life (see Discourse II). He left the army in 1623 and, after a short stay in Paris, settled in the relatively tolerant Dutch Republic. In 1637 he published the Discourse on the Method; in 1641 the Meditations on First Philosophy; and in 1644 the Principles of Philosophy. These works attracted considerable controversy, and in 1649 Descartes accepted an offer to move to Sweden as tutor to Queen Christina, an admirer of his work. Unfortunately the harsh climate and early morning lessons undermined Descartes’ health and he died of pneumonia in February 1650.
Descartes lived at the time of a revolution in scientific thought. The seventeenth century would witness the discoveries of Kepler, Galileo, Harvey, Boyle, Hooke and ultimately Newton. This new science would replace the outdated Aristotelianism refined in the late Middle Ages by Scholastic philosophers under the watchful eyes of the Catholic Church. Scholastic science offered a natural philosophy based around qualitative explanations. For example, falling objects were thought to possess a quality of heaviness; liquids of wetness; and so on. Such descriptions were hardly explanations at all, and were often notoriously obscure. A new type of explanation was needed, one that used mathematics to identify and reveal the hidden laws of nature.
Descartes was a scientist of his time, and played a crucial and influential role in the scientific revolution. Although remembered for his contributions to Philosophy, he published material on Geometry, Mechanics, Physics, Cosmology, Meteorology, Optics and much more. He was, of course, a first-class mathematician and some of his ideas – Cartesian coordinates, for instance, and a number of algebraic innovations – are still in use today. This allowed him to develop a quantitative account of the physical world in the manner of Galileo: Descartes’ physics describes a single continuum of matter in motion, governed by simple mathematical laws like inertia and conservation of motion. The new science offered a fully mechanical account of a universe that ran like clockwork.
As the example of Galileo vividly shows, the new science was not without opposition. Three aspects were particularly threatening to the church authorities. Firstly, the Copernican model of a planetary system with the sun at its heart displaced humanity from the centre of the universe and appeared to contradict the Bible. Secondly, the clockwork universe left little room for God to involve himself in human affairs. Thirdly, the ability of human reason to penetrate the mysteries of the universe was a serious blow to the epistemic authority of a church already reeling from the Reformation. In the Middle Ages, the church had fostered and supervised almost all aspects of learning and discovery. Men like Descartes, however, represented a new breed of secular intellectuals working outside the control of the church. With the collapse of the old medieval certainties, and the rise of the new science, came a renewed interest in scepticism. For the first time in many centuries, people were starting to doubt.
Descartes’ philosophical masterpiece, the Meditations on First Philosophy, was published in Paris in August 1641. The manuscript had been circulated to a number of scholars before publication, and the first edition also contained six sets of Objections together with Descartes’ (sometimes testy) Replies. These scholars were for the most part highly distinguished, and included the materialist Thomas Hobbes, the empiricist Pierre Gassendi and the theologian Antoine Arnauld. Each presented telling objections to Descartes’ arguments. The following year a second edition was produced in Amsterdam containing a seventh set of Objections by the Jesuit Pierre Bourdin. Descartes’ original text is written in Latin, the commonly accepted academic language of the time, although it was translated into French for wider consumption in 1647.
The Meditations are modelled after popular religious meditations – a series of daily readings encouraging reflection on matters of faith. Descartes’ work is written in the first person and the present tense, and the reader is asked to share and contemplate Descartes’ discoveries with him over the course of six days. As Francks notes (p190 fn90), Descartes – like God before him – labours for six days to make the world (anew) and rests on the seventh. There is, accordingly, an element of fiction about the Meditations (Descartes is not discovering these truths as he writes) which makes them both highly readable and attractive to the curious mind.
The ideas of Descartes dominate the philosophy of the seventeenth century and remain influential up to the present time. The Meditations in particular represent a new focus on epistemology, and attention to the methodological issues involved in acquiring knowledge. Descartes’ approach is generally termed rationalist in contrast with the empiricist approach of John Locke and his successors in the English-speaking world. Rationalism is characterised by the belief that reason has precedence over other ways of knowing; certain concepts – including God, substance, cause, self – seem to outstrip experience and must therefore be innate and knowable a priori. In Descartes’ case, he explicitly intends to lead the mind away from the senses (Synopsis p9). The usual paradigm of knowledge for rationalists is mathematics, and Descartes is no exception: geometrical or arithmetical examples abound in the Meditations to illustrate the certainty and accessibility of knowledge.
However, Descartes was as much scientist as rationalist, and his metaphysical reflections are intended ultimately to provide a more secure foundation for the empirical and practical sciences. In his preface to the French translation of the Principles, Descartes describes systematic knowledge with an organic metaphor:
... the whole of philosophy is like a tree. The roots are metaphysics, the trunk is physics, and the branches emerging from the trunk are all the other sciences, which may be reduced to three principal ones, namely medicine, mechanics and morals.
The Meditations therefore examine the roots of this tree: metaphysics (or ‘first philosophy’ to use the Aristotelian term) will provide a justification and basis for the whole scientific project.
In a letter to Marin Mersenne (the scholar responsible for collating the Objections), Descartes confessed that the Meditations’ subtitles were ‘the things I want people mainly to notice’. These subtitles draw attention to the more orthodox aspects of the work, namely the proofs of the existence of God and the soul. He was also aware, however, that the implications of his metaphysics as a whole were far from orthodox:
I hope that readers will gradually get used to my principles and recognize their truth, before they notice that they destroy the principles of Aristotle. Sorell p55
Descartes’ concern is understandable. In 1633 Galileo had been condemned by the Roman Inquisition for teaching the Copernican theory and placed under house arrest. At the time, Descartes was working on a treatise called The World (Le Monde) which used the same theory: he immediately decided not to publish for fear of offending the church authorities. Descartes’ religious beliefs were sincere and traditionally pious, and he had no wish to engage in theological dispute. In fact, it seems that he believed that his philosophical system would (in the end) support traditional theology – it was only the Aristotelian natural philosophy that he was seeking to overturn. Throughout his works, Descartes is careful to distinguish between the physical, mechanical world of science, and the mental or spiritual world of religion. These two domains were totally separate, and the new science should have no effect on theology. Of course, the accelerating success of the physical sciences would soon come to eclipse religious authority. While the great scientists of the seventeenth century were pious men – Kepler, Bacon, Galileo, Descartes, Newton – the eighteenth century would witness the first modern atheists. It is hard not to recognise the influence of Descartes – however unintentional – in the rising tide of scepticism that would soon come to threaten religious belief.