Justified True Belief

(●) The soldier turned philosopher who pulled down everything he believed in order to see what would still be standing. + Imagine a man who owns a house he has lived in all his life, and who begins to suspect that some of the beams are rotten. He cannot tell which ones. So he does the drastic thing: he empties the house, takes it apart down to the ground, and puts back only the beams he has tested himself. That is what René Descartes did with everything he had been taught, and the philosophy that came out of it has been argued over ever since. He is usually called the father of modern philosophy, and the title is fair, though it is often said as an accusation. What is easy to forget is what he thought he was doing. Descartes was a practicing Catholic who dedicated his hardest book to the theology faculty of the University of Paris, and he believed he had given the church something it badly needed: proofs of God and of the soul’s survival that an unbeliever would have to accept, because they used nothing but reason and required no Bible on the table. Two centuries of Christian philosophy would run on the machinery he built, and two centuries of unbelief would run on it too. One signature fact, and it explains a good deal about him. He was a sickly boy, and the Jesuits who taught him are said to have let him stay in bed in the mornings while the other students went to lessons. He kept the habit for the rest of his life, said his best thinking was done there, and it lasted until a queen of Sweden asked him to teach her philosophy at five in the morning. That request killed him inside four months.

(●) 1596 AD: Born into a family of lawyers in Touraine, he lost his mother before he could remember her. + René Descartes was born on 31 March 1596 in the small town of La Haye, in the Touraine country of central France, in his grandmother’s house. The town is called Descartes today. His father Joachim was a councillor in the parlement of Brittany, a high provincial court, which meant he was away at Rennes for most of the year; his mother, Jeanne Brochard, died in childbirth when René was thirteen months old. So the boy was raised by his grandmother and a nurse, in a household of comfortable means and considerable absence. He was small, pale, and often ill. Writing to Princess Elisabeth of Bohemia many years later, he said he had inherited from his mother a dry cough and a pale colour that stayed with him past the age of twenty, and that all the doctors who saw him in those years condemned him to die young. He outlived that verdict by half a century, and the habit of being left alone to think, which began as an invalid’s privilege, became the shape of his working life.

(●) 1607 AD: Eight years with the Jesuits gave him mathematics and took away his confidence in everything else. + At about ten or eleven he was sent to the Jesuit college of La Flèche in Anjou, one of the best schools in Europe and only a few years old. He stayed until he was eighteen. The Jesuits gave him Latin, Greek, logic, the physics and metaphysics of Aristotle as the medieval schools had developed them, and, in the final years, mathematics. He described the experience later with a mixture of gratitude and dismay. The teaching had been the best available anywhere, and that was exactly the problem: if the best available teaching still left every question open, then the trouble lay deeper than any one school. In philosophy, he wrote, nothing was free from dispute and therefore nothing was certain, while in mathematics he had found reasoning so exact that a conclusion could not be argued with once the steps were seen. He came away with one question that would occupy him for the next thirty years. Why should the rest of human knowledge not be like geometry? He took a law degree at Poitiers in 1616, as a lawyer’s son was expected to, and never practiced.

(●) 1619 AD: A soldier in winter quarters, shut in a heated room, he dreamed three dreams and settled his life’s work. + Rather than practice law, Descartes went soldiering, which for a gentleman of his class was a way of seeing the world at someone else’s expense. In 1618 he joined the army of Maurice of Nassau at Breda, in the Dutch Republic, and there he met a man who changed him. Isaac Beeckman was a Dutch schoolmaster and physician with an appetite for physics, and he took the young Frenchman seriously as a mathematician when nobody else had. Descartes wrote a short treatise on the mathematics of musical harmony for him as a New Year’s gift. The following winter he was with a different army, that of Maximilian of Bavaria, and the season caught him in a town in southern Germany. Which town is not certain: Adrien Baillet, whose 1691 life of him is the fullest of the early accounts, says Neuburg on the Danube, and other evidence points to Ulm. What he tells us himself is that with no company to distract him he spent the whole day shut up alone in a stove-heated room, thinking. On the night of 10 November 1619 he had three dreams, and he took them, in the manner of his century, as a sign. He wrote in a private notebook that he had discovered the foundations of a wonderful science, and Baillet reports that he vowed a pilgrimage to the shrine of Loreto in Italy in thanks. The notebook itself is lost; what survives of it is a partial copy Leibniz made in 1676 and the passages Baillet quoted. He was twenty-three. He had no book, no system, and no position. What he had was the conviction, which never afterward left him, that all the sciences were one science, and that a single method would unlock them.

(●) 1628 AD: He left France for the Dutch Republic, where a man could be left alone, and stayed twenty years. + The 1620s went by in travel and in Paris, where he was known in the circle around Marin Mersenne, a friar of the Minim order, one of the austere religious orders of the day, who kept up a correspondence with half the scientists in Europe and functioned as a one-man postal service for the new science. Descartes began a book of method, the Rules for the Direction of the Mind, and abandoned it unfinished. Late in 1628 he moved to the Dutch Republic, and apart from short visits he did not live in France again. The Netherlands suited him: a Protestant country with a booming print trade, a tolerance for awkward opinions that no Catholic kingdom could match, and above all crowds of strangers who had no interest in him. He changed lodgings constantly, from Franeker to Amsterdam to Leiden to Egmond, and kept his address from all but a few correspondents. Baillet reports that he took a line adapted from Ovid’s Tristia as his motto: bene vixit, bene qui latuit, he has lived well who has hidden well. Two things belong to these Dutch years that his admirers often skip. In July 1635 a servant in the house where he had lodged in Amsterdam, Helena Jans van der Strom, bore him a daughter, Francine. He had himself entered as her father in the baptismal register at Deventer, though to most of his acquaintance he called the girl his niece, and he made plans for her schooling. And it was here, in the quiet he had bought at the price of exile, that he wrote everything he is remembered for.

(●) 1633 AD: News of Galileo’s condemnation reached him with his book finished, and he put it in a drawer. + By the autumn of 1633 Descartes had all but completed a treatise called The World, a full physics of the universe built out of matter and motion, and it took for granted that the earth goes round the sun. He was arranging to have it printed when word came from Italy that the Roman Inquisition had condemned Galileo Galilei and forced him to abjure that very claim. He wrote to Mersenne in November that he had been so astonished by the news that he almost decided to burn all his papers. A few months later, in the spring of 1634, he told the same correspondent that he would not publish a book containing a single word the church disapproved of, and that he preferred to suppress it rather than bring it out in a mutilated form. He did suppress it. The World did not appear until fourteen years after his death. It is worth being honest about the decision, because it was not simple cowardice and it was not simple obedience. Descartes was a loyal son of his church living safely out of its reach, in a country where he could have printed anything he liked. He chose silence anyway, partly from real deference and partly from a settled distaste for controversy that ran through his whole character. When he did publish, four years later, he published in French rather than Latin, anonymously, and led with the parts nobody could condemn.

(●) 1637 AD: In seven years he published the three books that made him, and buried the only child he had. + The Discourse on the Method came out at Leiden in 1637, in French, as a preface to three scientific essays on optics, weather, and geometry. The last of the three quietly founded a new branch of mathematics by showing that a curve can be written as an equation and an equation drawn as a curve, which is why schoolchildren still plot points on what are called Cartesian coordinates. The preface, meanwhile, contained the most famous four words in modern philosophy. Then, on 7 September 1640, Francine died of scarlet fever at Amersfoort after three days’ illness. She was five years old. Writing to a friend a few months afterward, Descartes said he was not one of those who hold that tears and sadness belong only to women, and Baillet reports that he called her death the greatest regret he had ever felt in his life. He had been arranging to bring her to France for her schooling. The Meditations on First Philosophy appeared the following year, in Latin, dedicated to the dean and doctors of the theology faculty at Paris. Descartes had done something unusual with it: before printing, he circulated the manuscript to the sharpest minds he could find and published their attacks alongside his replies. Six sets of objections came in the first edition, from a Dutch priest, from Mersenne, from Thomas Hobbes, from the theologian Antoine Arnauld, from the philosopher Pierre Gassendi, and from a committee; a seventh, by a Jesuit, was added in 1642. The Principles of Philosophy followed in 1644, a textbook meant to replace Aristotle in the universities. None of it went quietly. At Utrecht, the rector Gisbertus Voetius, a Calvinist theologian of formidable seriousness, looked at the new philosophy and saw a solvent that would dissolve religion, and in 1642 he got the university senate to condemn it. The quarrel turned personal, and then it turned legal. By 1643 the Utrecht magistrates had come close to prosecuting Descartes for slander and were threatening to burn his books, and the affair was quieted only when powerful friends, the French ambassador among them, took his part. That same year a very different reader wrote to him. Elisabeth, princess of Bohemia, was twenty-four and living in exile at The Hague, and she put to him the one question about his system that he never satisfactorily answered.

(●) 1650 AD: A queen wanted her lessons at five in the morning, and a Stockholm winter killed him. + Christina of Sweden was twenty-two, ruled a great Protestant power, collected scholars the way other monarchs collected paintings, and would not be refused. She sent a warship. In October 1649 Descartes arrived in Stockholm. The arrangement was as bad as it could have been designed to be. The queen’s hours were early, and she wanted her philosophy lessons in her library at five in the morning, three days a week, through a Swedish winter that drew from him, in a letter of 15 January 1650, the complaint that men’s thoughts freeze there as the water does. He had been rising at eleven for most of his life. Alongside the lessons he was drafting statutes for a new academy, and a set of verses for a court ballet danced before the queen in December 1649 has long been printed among his works, though whether he wrote them is disputed. He fell ill at the beginning of February 1650 with an inflammation of the lungs, and died on 11 February, seven weeks short of fifty-four. A Catholic in a Lutheran capital, he was buried in a graveyard reserved for unbaptized infants. Sixteen years later his remains were carried back to France, and they rest now in the church of Saint-Germain-des-Prés in Paris, though his skull went astray along the way and sits in a Paris museum. His books, meanwhile, went to Rome: in 1663 the Congregation of the Index placed the whole corpus on the list of prohibited works, pending correction.

What He Taught

(T1) Doubt everything that can possibly be doubted, and one thing is still there: the doubter. + Suppose you found one rotten apple in a basket. The sensible thing is not to pick through the basket where it stands, since you will get tired and miss one; the sensible thing is to tip the whole lot out and put back only the apples you have looked at. Descartes uses exactly that picture when he answers the last of his objectors, the Jesuit Pierre Bourdin, and it is his method in one image. So he tips the basket. He begins with the senses, which deceive us now and then, as anyone knows who has watched a straight oar bend where it enters the water, and his rule is that whatever has fooled him once he will treat from then on as untrustworthy. That puts the whole evidence of sight and touch on the floor. Then he comes to dreams. Every night of his life he has been persuaded by scenes that were not there, and while he is inside one of them he cannot tell the difference from waking, so ordinary waking experience goes the same way. That still leaves arithmetic, since two and three make five whether the man adding them is asleep or awake. To shift even that, he imagines an evil deceiver of enormous power whose whole business is to fool him, and by the end of the first Meditation every belief he owns is lying on the floor with the apples. And then the floor holds. If he is being deceived, there has to be someone there to deceive. The very act of doubting is a piece of thinking, and thinking cannot go on with nobody doing it. In the French of the Discourse the conclusion runs je pense, donc je suis, four words in English, "I think, therefore I am"; in the Meditations he puts it more carefully as "I am, I exist," true every time he says it or thinks it. Two things about that first certainty are worth holding on to. It is not an inference from a premise, as though existence were being deduced from thinking the way rain is deduced from wet pavement; it is one thing seen in a single act, which is why later critics who attacked the logic of it were often attacking something Descartes had not said. And it is thin. All it delivers is that a thinking thing exists. There is as yet no world, no body, no past. Everything else has to be earned back, and the next thing he reaches for is God.

(Q) "But immediately upon this I observed that, whilst I thus wished to think that all was false, it was absolutely necessary that I, who thus thought, should be somewhat; and as I observed that this truth, I think, therefore I am (COGITO ERGO SUM), was so certain and of such evidence that no ground of doubt, however extravagant, could be alleged by the sceptics capable of shaking it, I concluded that I might, without scruple, accept it as the first principle of the philosophy of which I was in search." + Source: Descartes, Discourse on the Method, Part IV (Veitch translation). Veitch’s old-fashioned "should be somewhat" means "had to be something," and the Latin in capitals is his own insertion, since Descartes wrote the sentence in French. At this point in the Discourse Descartes has spent a page throwing out the senses, the world, and his own body, and this is the sentence where the demolition stops.

(T2) The idea of a perfect God is too big to have come from me, so God exists. + Here is the puzzle Descartes sets. He is alone with his own mind, and among the contents of that mind he finds an idea of God: a being infinite, eternal, unchanging, all-knowing, all-powerful, on whom everything else depends. Where did a small, ignorant, changeable creature get an idea that size? Not from the senses, since nobody has seen infinity. Not by patching it together out of experience, the way one makes a unicorn out of a horse and a horn, because you cannot manufacture the infinite by adding finite pieces; a stack of finite quantities is only ever a bigger finite quantity. Not by taking himself and improving on the picture, because he can only recognize himself as imperfect if he already has the perfect to measure against. What is left is a principle he thought no one could deny once it had been said out loud: an idea must have a cause with at least as much reality in it as the idea represents. Think of a painting of a cathedral. The paint did not invent the cathedral; something at least as grand as what is in the picture stands behind the picture, whether that is the building itself or the mind of an architect who could imagine it. And a small, changeable, half-informed creature is not grand enough to stand behind an idea of the infinite. Only God is. So God put it there, and Descartes gave the thought its best image: the maker’s mark, stamped on the work. Modern readers call this the trademark argument. The nickname is theirs rather than his, though the proof is entirely his. In the fifth Meditation he adds a second and much older one, the ontological argument, first framed by Anselm of Canterbury in the eleventh century: God is by definition supremely perfect, and a supremely perfect being that did not exist would be missing a perfection, so existence belongs to the idea of God the way having three angles belongs to the idea of a triangle. You cannot think a mountain without a valley, Descartes says, and you cannot think God without existence. The proofs are doing heavy lifting in his system, and not only religious lifting. Having reached God, he can argue that a perfect being would not be a deceiver, and therefore that the mind God gave him is not systematically lying to him. That last step is where a phrase of his own gets its licence, and it is worth learning, because everything else in his philosophy leans on it. To perceive something clearly and distinctly, in Descartes’ vocabulary, is to have it in front of the mind so plainly, and so cleanly separated from everything it is not, that while you are actually looking at it you cannot make yourself doubt it. A man checking a small sum on paper is in that position: while two and three and five are all in front of him, the doubt has nowhere to stand. A good God would not build a mind that goes wrong in exactly those moments. So the evil deceiver of the first Meditation is dismissed by the goodness of the real God. That is the hinge on which everything after it turns: without God, Descartes is left with nothing but himself.

(Q) "And one certainly ought not to find it strange that God, in creating me, placed this idea within me to be like the mark of the workman imprinted on his work; and it is likewise not essential that the mark shall be something different from the work itself." + Source: Descartes, Meditations on First Philosophy, Meditation III (Haldane and Ross translation). A craftsman stamps his name on what he makes. Descartes is saying that the idea of God in a human mind is that stamp, and that the stamp need not be a separate thing from the work: the mark God left is the human being’s own capacity to know him. The sentence just after it says that in creating him God has placed his image and likeness upon him (T2).

(T3) Mind and body are two entirely different kinds of thing, and the mind is the better known of the two. + Take a lump of beeswax from a hive. It smells of flowers, it is cold, hard, and pale, and it makes a sound if you tap it. Hold it near the fire and every one of those qualities goes: the scent leaves, the colour changes, it softens, it will not ring. Yet you have no doubt at all that it is the same wax. So what did you know the wax by? Not by any of the things your eyes, nose, or fingers reported, since all of those changed. You knew it by an act of the mind, and Descartes points out the sting in the tail: this little exercise, which was supposed to tell him about wax, has told him more about the mind that judged it. That is the road into his most consequential doctrine. Descartes divides created reality into two kinds of substance, that is, two kinds of thing that exist in their own right. There is res extensa, extended stuff, whose whole nature is to take up space: it has size, shape, and position, it can be divided, and everything true of it is in principle a matter of geometry. And there is res cogitans, thinking stuff, whose whole nature is to be conscious: it doubts, understands, wills, imagines, feels. Thinking stuff has no shape and no location and cannot be cut in half. Since he can form a clear idea of himself as a thinking thing with no body at all, and a clear idea of body as extended and mindless, the two must really be distinct, and the soul can therefore survive the body’s death. This is what philosophers mean by Cartesian dualism. Descartes knew perfectly well that a soul merely riding in a body was not what he had to explain. He insisted, in a fine phrase, that he is not lodged in his body as a pilot in a ship, since a pilot feels no pain when his ship is damaged, whereas hunger and thirst and pain are felt from the inside as one’s own. So the two are genuinely joined. How? He guessed at the pineal gland, a small structure at the centre of the brain, as the place where the joining happens. The guess was weak and the best objection came from a friend. Princess Elisabeth of Bohemia wrote to him in 1643 and asked, politely and devastatingly, how something with no extension and no surface could push a body around, given that everything he had said about how bodies move requires contact and shape. He tried several answers and satisfied neither her nor himself. The question has a name now, the mind-body problem, and it is still open.

(Q) "And although possibly (or rather certainly, as I shall say in a moment) I possess a body with which I am very intimately conjoined, yet because, on the one side, I have a clear and distinct idea of myself inasmuch as I am only a thinking and unextended thing, and as, on the other, I possess a distinct idea of body, inasmuch as it is only an extended and unthinking thing, it is certain that this I [that is to say, my soul by which I am what I am], is entirely and absolutely distinct from my body, and can exist without it." + Source: Descartes, Meditations on First Philosophy, Meditation VI (Haldane and Ross translation). The words in square brackets are the translators’ own signal that they come from Descartes’ French edition of 1647, where the printed Latin is shorter. This is the sentence the whole book was built to reach. The title page of the first edition promised a demonstration of the immortality of the soul, and this is where the demonstration lands: if soul and body are two things rather than one, the death of one is not the death of the other (T3).

(T4) The physical world is nothing but stuff taking up space, pushed about by other stuff. + Ask an Aristotelian schoolman of 1600, one of the university men who taught natural philosophy out of Aristotle, why a stone falls, and he will tell you the stone is heavy, meaning that heaviness is a real quality in the stone which inclines it toward its natural place. Ask why fire burns and he will speak of the form of fire. There were dozens of such qualities and forms, one for each kind of behaviour, and the explanations had a way of restating the thing to be explained. Molière would get a laugh out of the pattern on the Paris stage a generation later, with a doctor explaining that opium sends a man to sleep because it has a sleep-making power in it. Descartes threw the lot out. Matter, he argued, has exactly one property: extension, taking up length, breadth, and depth. Hardness is not in the stone; it is what happens when the parts of one body resist the motion of your hand. Colour is not in the rose. Heaviness is not a striving. Everything that happens in the physical world happens because portions of extended stuff are shoved about by other portions, and physics is therefore geometry plus motion, nothing more. He denied empty space outright, since extension is what matter is, and filled the heavens with a fluid carried round in great whirlpools, or vortices, which sweep the planets along like straws in an eddy. Most of the physics was wrong. He did get one large thing right, that a moving body keeps moving in a straight line until something else stops it or turns it, which is the rule schoolchildren now learn as inertia; but Newton, born eight years before Descartes died, would show that the vortices could not produce the orbits the sky actually shows. What survived was the ambition, and it was enormous. He set out a universe running on a few laws that hold everywhere, and he grounded those laws in the character of God: God preserves the quantity of motion in the world because God does not change his mind, so nature is uniform because its author is constant. That thought did not begin with Descartes and it did not end with him, but he pressed it harder than anyone before, and the working assumption of physics ever since has been the one he made. He pressed it further than most Christians have been willing to follow, and the place it broke is worth marking. If matter is only extension in motion, then a living animal is a very complicated machine and nothing else, with no mind and no inner life at all. Descartes said so plainly and drew the conclusion in public.

(Q) "In this way we will discern that the nature of matter or body, considered in general, does not consist in its being hard, or ponderous, or coloured, or that which affects our senses in any other way, but simply in its being a substance extended in length, breadth, and depth." + Source: Descartes, Principles of Philosophy, Part II, article 4 (Veitch translation). "Ponderous" means heavy. The Principles was written to be taught, laid out in short numbered articles so that a university could put it in students’ hands in place of Aristotle. Descartes hoped his old teachers the Jesuits would adopt it. They did not, and it was in the Dutch universities, over their theologians’ loud objections, that his physics first got taught (T4).

(Q) "I have always considered that the two questions respecting God and the Soul were the chief of those that ought to be demonstrated by philosophical rather than theological argument." + Source: Descartes, Meditations on First Philosophy, dedicatory letter to the Dean and Doctors of the Sacred Faculty of Theology in Paris (Haldane and Ross translation). The opening of the letter with which he handed the Meditations to the theologians of the Sorbonne. His reasoning is stated a few lines further on: believers can take God and the soul on faith, but an unbeliever will not be moved by Scripture, and to argue from Scripture that Scripture is trustworthy is to walk in a circle. So the two doctrines that unbelief most needs must be proved by reason alone. Whether he pulled it off is the question the next three and a half centuries have been arguing about.

What Christian Thinkers Made of Him

(†) Within a generation his philosophy had split the universities, and it was Christians on both sides of the split. + Nothing about the reception was tidy, and the official verdicts ran one way while the reading ran another. In the Dutch Republic, Henricus Regius was teaching Cartesian physics at Utrecht in his medical lectures before the Meditations was even printed, which is what brought Voetius to the university senate to have it condemned. Leiden followed in 1647 with a ban of its own, forbidding its teachers to so much as name him in a lecture. Rome came next, the Congregation of the Index prohibiting the works in 1663, and in France Louis XIV’s government eventually forbade their teaching in the schools. And all the while Cartesianism spread anyway, partly because it was clearer than what it replaced, and partly because he had written it in French, which put it in the hands of anyone who could read. The most interesting thing about the fight is who was on which side. Antoine Arnauld, the great theologian of Port-Royal and no man’s idea of a sceptic, wrote the sharpest of the objections to the Meditations and then spent much of his life defending Descartes; the Port-Royal Logic he helped write carried Cartesian method into the schoolrooms of Catholic Europe. Nicolas Malebranche, an Oratorian priest, came across the posthumous Treatise on Man at a bookstall in the rue Saint-Jacques in 1664 and, his own biographer reports, was so shaken by it that he had to stop reading to catch his breath. He built from it a whole theology in which God is the only true cause and creatures merely the occasions on which he acts. And by the end of the century the alarm had reached the top: Bossuet, the most powerful churchman in France, was warning his correspondents that a great battle was being prepared against the church under the name of Cartesian philosophy. The reason the fight was so hard is that Descartes had handed the church a genuinely double-edged gift. He had given apologetics two fresh proofs of God and a proof of the soul’s distinctness from the body, and he had given them at a moment when Europe badly needed them. Ancient atomism was being read again, the old Greek doctrine that everything there is amounts to small particles moving about in empty space, which carries with it the conclusion that a person is a heap of particles and that nothing at all survives when the heap comes apart. Against that, his proofs were very nearly the weapons the church would have asked for. That is the one edge. The other is that he had made the certainty of God rest on the reasoning of an individual mind sitting alone by a fire.

(†) The proofs he left are still in use among Christian philosophers, and Princess Elisabeth’s objection is still unanswered. + Three of his pieces are still in working use by Christian philosophers, which is a longer life than most seventeenth-century philosophy has managed. - The ontological argument. Descartes took Anselm’s argument out of the cupboard where Aquinas had left it, and although Kant thought he had finished it off in 1781 by insisting that existence is not a property, it came back. Norman Malcolm restarted the discussion in 1960, and Alvin Plantinga later recast it using the logic of possibility and necessity. A being of maximal greatness, in that recasting, is one that is not merely great in the world as it happens to have turned out, but exists and is unsurpassable in every way things could have gone; and if such a being is so much as possible, then it exists. The debate over that argument is live today. - Dualism. The claim that a human being is not simply a physical object has become a minority position among philosophers, but it is a well-defended minority, and Christian philosophers such as Richard Swinburne and J. P. Moreland argue versions of it that answer objections Descartes never faced. Scripture nowhere teaches Descartes’ particular theory, but it does speak of a person who would rather be away from the body and at home with the Lord (2 Corinthians 5:8), and Christians who reject his two-substance account still have to say something about that. - God as the ground of knowing. Strip away the machinery and Descartes’ boldest claim is that unless a good God stands behind the mind, there is no reason to trust it. That structure has had a long career. It runs through Alvin Plantinga’s argument that naturalism, the view that nature is all there is and that nothing stands behind it, cannot be held together with evolution without undercutting confidence in our own faculties, and it is the philosophical shape of an old line of Scripture: "For with you is the fountain of life; in your light do we see light" (Psalm 36:9). The question he could not answer has had an equally long career. Elisabeth of Bohemia’s challenge, how a mind with no size or surface can move a body, is the standing objection to dualism in every philosophy department today, and no Christian who holds that human beings are more than matter can afford to wave it away.

(†) He reached God at the end of an argument, never untied the circle Arnauld found in his reasoning, and taught that animals feel nothing. + Descartes died a believing Catholic, and what follows is a criticism of what he built rather than of whether he meant well. - The circle. Arnauld put it first and it has never gone away. Descartes trusts whatever he perceives clearly and distinctly only because a good God would not deceive him; but he reaches that good God by a chain of reasoning whose every link is something he perceives clearly and distinctly. So the rule seems to rest on God and God seems to rest on the rule. Descartes replied that the rule is not in doubt while a proof is actually before the mind, and that God is needed only to secure conclusions one is remembering rather than currently seeing. Many readers have not found that enough, and the Cartesian circle is a standard entry in every history of philosophy. - The God of the argument. Pascal, a mathematician of the next generation and a Christian who had met God in a way Descartes never described, wrote in his notes: "I cannot forgive Descartes. In all his philosophy he would have been quite willing to dispense with God. But he had to make Him give a fillip to set the world in motion; beyond this, he has no further need of God" (Pensées 77, Trotter translation). A fillip is a flick of the finger, the sort that sends a marble rolling across a table and is then done with it, which is exactly the picture Pascal wants. The complaint is not that the proofs fail. It is that a God who functions as a guarantee of clear ideas is not obviously the God who called Moses out of a bush or wept at a grave, and that Descartes never seems to notice the difference. Scripture is blunt about the limits of the method: "For since, in the wisdom of God, the world did not know God through wisdom, it pleased God through the folly of what we preach to save those who believe" (1 Corinthians 1:21). What is proved in a study is not yet what is preached (Matthew 11:25). - The beast-machine. Because he had defined matter as extension in motion and mind as a separate substance given to human beings, Descartes concluded that animals have no minds at all. Not less reason than ours: none. A dog that yelps under the wheel is a mechanism producing a noise. He argued the point from language, holding that even the dullest human child can put words together to say something new while no animal ever does, and he wrote in the Discourse that this proves not only that the brutes have less reason than man, but that they have none at all. He meant the doctrine kindly in one respect, since it spared him from having to say that animals suffer unjustly, and he did not say cruelty to animals was permitted. But the doctrine is false to Scripture and to ordinary sight. Genesis has God make the living creatures and call them good before any human is there to observe them (Genesis 1:24-25), the fourth commandment gives the Sabbath rest to a man’s livestock along with his household (Exodus 20:10), and Proverbs measures a man by how he treats his animals: "Whoever is righteous has regard for the life of his beast, but the mercy of the wicked is cruel" (Proverbs 12:10). Here the tidiness of the system beat the evidence, which is the characteristic danger of a mind like his. There is one more thing to say, and it belongs on the credit side of the same ledger. Descartes began his philosophy alone, from the inside, with the self as the first thing certain and everything else, God included, reached by argument from there. That was a genuine discovery about how much a mind can establish on its own, and it was also a decision about where to stand. Scripture begins somewhere else. It opens not with a man certain of himself but with God speaking, and it says that what can be known about God is plain, perceived ever since the creation of the world in the things that have been made (Romans 1:19-20), so that the knowledge of God is not an achievement of method but a given that people suppress. Descartes proved more about God than most philosophers ever manage. He also taught the West to look for God at the far end of an argument, and there is no sign in anything he wrote that he saw what that would cost.