Empiricism

Pierre Bayle.

Not every seventeenth-century intellectual engaged in scientific research embraced rationalism. Some rejected it as presuming to use mathematics to do something mathematics could not do, that is, validate the existence of God. Of these, the most important was Blaise Pascal (1623–1662), the French genius whose Jansenist convictions prompted him to affirm that God is only knowable through the insights he offers as gifts of grace to individual humans. Those trained in the traditional concerns of humanism, with its emphasis on creating a philosophy that might inspire virtue, similarly failed to concede the high road to the rationalists. Many thinkers who could be placed in this category adopted a skeptical posture that questioned the value of any knowledge of human affairs derived from scientific methods of reasoning. Of these, the most influential was Pierre Bayle (1647–1706). Bayle was born and raised as a French Huguenot, those that followed the teachings of John Calvin. For a brief period he converted to Catholicism, although his re-conversion to Calvinism necessitated his flight from France. Ultimately, he settled as a free man in Rotterdam, but he did so with the knowledge that the French government had imprisoned his brothers as punishment for his writings. They would eventually die in jail. Even in Rotterdam, clerical authorities attacked Bayle for the apparent atheism articulated in his writings. The trials and tribulations Bayle experienced because of his religious views made him a bitter opponent of any and all dogmas—proclamations of truth—whether they be religious, scientific, or otherwise. As Voltaire later characterized him with some hyperbole, Bayle had the finest mind for the "art of reasoning"—that is, critical analysis—of any intellectual "who ever wrote." Bayle slowly examined any claim of truth and worked through its arguments to show the doubts about it every rational person had to recognize. One example of Bayle's method was his discussion of "identity." Since Descartes had based his proof of existence on consciousness, early-modern thinkers debated whether identity was continuous—whether a person has the same consciousness today that he or she had five days ago or five years ago. To a "learned theologian" who affirmed that consciousness is retained, Bayle posed the questions: "How do you know that, this morning, God did not let your soul fall back into nothing?" and "How do you know that God did not create another soul with the same modifications?" As Bayle concluded, "That new soul is the one you have now. Convince me to the contrary." Bayle's influence over philosophy stemmed from his Dictionnaire historique et critique (Historical and Critical Dictionary; 1702), a vast compendium of more than nine million words that was an international best-seller throughout much of eighteenth century. The articles in the dictionary were fairly straightforward. It was in his footnotes, though, that Bayle got into trouble. These were filled with the same relentless skepticism and questioning spirit that took no assumptions for granted that were found in all of Bayle's writings. While he insisted that he was a believing Christian, he nevertheless compiled a significant body of works that were questioned, even in his own lifetime, as a challenge to his own religion. Recent scholarship may have become more supportive of the idea that Bayle's confessions of faith were sincere, yet eighteenth-century philosophers who followed him were convinced of his questioning spirit and his use of human reason to undermine Christian teachings. Bayle's work was particularly important for its impact on rationalistic arguments. His writings successfully assaulted the rationalists' assumptions that mathematical reasoning could bring certainty to questions about human existence. In this way his work cleared the ground for the coming of empiricism, a school of philosophy that championed human observation and the insights it might offer.

Epicureanism.

By the second half of the seventeenth century, philosophical thinking in Europe had come to an impasse. Outside of clerical circles the traditional methods of university scholasticism had almost no appeal. Humanism, too, with its emphasis on ancient textual and literary study, was incapable of making sense of the ongoing discoveries that were occurring in science and beyond Europe's boundaries in the journeys of exploration. Much of the new knowledge that was being amassed at the time, too, derived from new technologies like the telescope that extended the power of the human senses. For all these reasons, rationalism, with its rejection of the possibility of learning new things through the senses, left many people, but especially scientists, cold. In the works of Bayle can be seen some of the tensions of the age, and some scholars have long pointed to his work as a prime example of a resurgence of skepticism in the era. At the same time, the rapid rise of empiricism, a movement that, in fact, grew from Bayle's very questioning cast of mind, cautions against an interpretation that points to a widespread resurgence of skepticism. It would be wrong to present the second half of the seventeenth century as waiting in anticipation of empiricism. Since modern philosophers continue to live in an intellectual universe where empiricist assumptions predominate and because they can look back and see this universe being born in the second half of the seventeenth century, it is useful to appreciate how empiricism fit with the European cultural sensibilities that were emerging in the seventeenth century in ways that no philosophical tradition has before, or since, been able to match. The key assumption of empiricism is the idea that knowledge comes through sensory experience. In contrast to rationalism's affirmation of innate ideas, empiricism insists that a reality exists outside and beyond the human mind, and that it is through the senses that humans gain an understanding of this reality. Like rationalism, empiricism's roots can be traced back to ancient Greek thought, specifically to the ideas of the Greek philosopher Epicurus (361–270 b.c.e.). Two of his conclusions were especially important to the later history of European empiricism. First, Epicurus recognized that the universe was made up of matter. From Democritus (460–370 b.c.e.) he derived a conception of the universe as a void or vacuum populated by atoms, which both figures understood to be irreducible, microscopic bits of matter. These atoms combined to create the macroscopic entities perceivable in the world. Epicurus added to Democritus the ideas that atoms have weight and thus naturally move in a downward direction, and that when atoms come together to form macroscopic entities, they coalesce in recognizable patterns that grant those entities discernible qualities such as the sweetness of honey or the whiteness of snow. It is worth stressing that the materialism implicit in Epicurus' notion of the universe also proved attractive to later seventeenth-century European thinkers. But Epicurus rejected the existence of a spiritual world. As noted before, many commentators recognize Francis Bacon's ideas as the source from which early-modern European scientists drew inspiration. This argument is true in the sense that Bacon's ideas provided a rationalization of scientific investigation upon which both scientists and the public could agree. On the epistemological level, however—that is, the level of the theory of knowledge—it was Epicurus who provided scientists with direction. His materialism, though, was an obstacle to the reconciliation of his ideas with Christianity. Many of the charges of atheism leveled at early-modern scientists and philosophers can be traced back to their use of the ideas of Epicurus. The second idea of importance from Epicurus is that human understanding comes via the senses. The patterns in which atoms configured themselves grant them qualities discernible only through the five senses. Epicurus affirmed that the senses never lied. Any confusion concerning sensory input takes place in the human mind. Thus the way to knowledge is through using the senses to correct the mind.

Gassendi and Boyle.

For most of the twentieth century scholars recognized John Locke as the initiator of the empiricist movement. Over the past few decades, however, the significance of the ideas of Pierre Gassendi (1592–1655) and Robert Boyle (1627–1691) as shapers of Locke's thought has been increasingly appreciated. Gassendi suffered from physical infirmities like his contemporary Malebranche, and like Malebranche opted to enter the priesthood, though he never ministered a parish. Gassendi was the first person to record the orbital progression of a planet (Mercury), and thus provide evidence in support of Johannes Kepler's laws of planetary motion. He was also the first scientist to identify and name the Aurora Borealis. It is perhaps revealing of the degree to which mathematics had taken over the debate concerning astronomy that in 1645, when Gassendi was honored for his achievements, he received a chair in mathematics at the College Royal of France. Gassendi was recognized as a scientist in his own day. History has remembered him, however, first and foremost as the individual who reintroduced Western civilization to the thought of Epicurus. Gassendi was one of the men invited to write comments on the first edition of Descartes' Meditations. Gassendi took exception to Descartes' appropriation of the methods of geometry and their application to the human quest for truth. For him, Descartes' "cogito ergo sum" proved nothing. Rejecting Descartes' claim that the pathway to truth traveled through the layers of the mind, Gassendi turned to the writings of Epicurus for proof that truth was something humans could only approximate. According to Gassendi, truth was reached through an inherently opposing process by which the senses acted against the mind to misinterpret the knowledge to which they were exposed. Gassendi believed in a "voluntarist" versus an "intellectualist" God, in other words, a God who does not just make laws but who actively shapes and reshapes those laws as he sees fit. From this perspective, Gassendi attacked Descartes' argument that mathematical forms such as triangles are eternal. As Gassendi understood it, if triangles were eternal, they would then stand as something external to God and his creation, a possibility Gassendi totally rejected. Triangles, therefore, must be part of the world God created. And as Gassendi cautioned, "Don't tell me if God destroyed it or established it otherwise, it would no longer be a Triangle." From this direction, Gassendi saw the atoms of Epicurus as serving God's command, and he sought to Christianize Epicurus, that is, to insert the Christian God as the animus or spirit in the materialistic universe that Epicurus had originally articulated. Thus whatever laws dictated the ways in which atoms came together, those laws had to be regarded as works in progress by God, who could and did, rework them over time according to his will. Gassendi's ideas were eagerly embraced in England by Robert Boyle, best remembered as the discoverer of the law that bears his name that summarizes the relationship between pressure and the volume of gases. A point of contention among seventeenth-century scientists was whether the universe consisted of a vacuum—a void—or a plenum—a filled space. Seeking to avoid a stand on the issue, Boyle labeled the irreducible bits of matter that make up the world "corpuscles," not atoms. But his corpuscles, like Gassendi's atoms, were God's building blocks. And while few people read Boyle for his corpuscular theory, the fact that Boyle explained his innumerable experiments based upon his corpuscular theory helped to diffuse his ideas among a broad readership.

John Locke.

Among the young men who helped Boyle with his many experiments was an aspiring medical student named John Locke (1632–1704). Although his skills as a medic were what brought Locke to the attention of his eventual patron, Lord Shaftesbury, Locke spent very little of his adult life practicing medicine. Eventually, his medical research provided him with qualifications for entering into the Royal Academy of Science, but Locke spent most of his time engaged in politics. Shaftesbury was a leader of the Whig party, which for most of the 1680s stood in opposition to King Charles II and his brother, who eventually took the throne as James II. Having failed in his effort to have the English Parliament exclude James from the succession to the English throne, Shaftesbury escaped England for exile in Holland in 1682, where he died less than a year later. As a close associate of Shaftesbury, Locke also felt it prudent to follow him into exile, and he remained in Holland until the Glorious Revolution of 1688 forced James from the throne. During the 1680s, while he was on the run from agents of the English crown, Locke composed An Essay Concerning Human Understanding (1690), the source text from which modern philosophical empiricism developed. In the Epistle or "Letter" that Locke provided as a prologue to this work, Locke treated his philosophy as deriving from the "scientific" ideas of figures like Boyle and Newton, the "master builders" he argued that had left "lasting monuments" for "posterity." His ideas were also shaped by the nature of the political-philosophical discourse that had occurred in England to this time. Although Thomas Hobbes's Leviathan (1651) remained fresh in the memory of English readers in Locke's day, this later philosopher came to far more optimistic conclusions than his predecessor had concerning the nature of humankind in a primitive state. His view of human psychology discarded the essential distrust and pessimism that had characterized Hobbes's earlier work. Locke portrayed his own work as an "under-laborer," inferior to the great achievements of Boyle and Newton. He was content, he wrote, to help "clear the ground" of some of the "rubbish that lies in the way of knowledge." In making this statement Locke expressed a sensibility that remains alive in the modern social sciences: the idea that the methods of investigation and analysis developed in the study of nature can be less loftily but still usefully applied to the task of clearing up some of the confusion or "rubbish" concerning humans and their behavior.

A BLANK SLATE

introduction: In his An Essay Concerning Human Understanding of 1690, John Locke discounted the notion of innate ideas, and set forth the idea that the mind was a "blank slate," or tabula rasa, at birth, upon which experience wrote its teachings. The idea was to become tremendously influential during the Enlightenment and to spark a great eighteenth-century inquiry into the nature of empirical knowledge.

For, first, it is evident, that all children and idiots have not the least apprehension or thought of them [innate ideas]. And the want of that is enough to destroy that universal assent which must needs be the necessary concomitant of all innate truths: it seeming to me near a contradiction to say, that there are truths imprinted on the soul, which it perceives or understands not: imprinting, if it signify anything, being nothing else but the making certain truths to be perceived. For to imprint anything on the mind without the mind's perceiving it, seems to me hardly intelligible. If therefore children and idiots have souls, have minds, with those impressions upon them, they must unavoidably perceive them, and necessarily know and assent to these truths; which since they do not, it is evident that there are no such impressions. For if they are not notions naturally imprinted, how can they be innate? and if they are notions imprinted, how can they be unknown? To say a notion is imprinted on the mind, and yet at the same time to say, that the mind is ignorant of it, and never yet took notice of it, is to make this impression nothing. No proposition can be said to be in the mind which it never yet knew, which it was never yet conscious of. For if any one may, then, by the same reason, all propositions that are true, and the mind is capable ever of assenting to, may be said to be in the mind, and to be imprinted: since, if any one can be said to be in the mind, which it never yet knew, it must be only because it is capable of knowing it; and so the mind is of all truths it ever shall know. Nay, thus truths may be imprinted on the mind which it never did, nor ever shall know; for a man may live long, and die at last in ignorance of many truths which his mind was capable of knowing, and that with certainty. So that if the capacity of knowing be the natural impression contended for, all the truths a man ever comes to know will, by this account, be every one of them innate; and this great point will amount to no more, but only to a very improper way of speaking; which, whilst it pretends to assert the contrary, says nothing different from those who deny innate principles. For nobody, I think, ever denied that the mind was capable of knowing several truths. The capacity, they say, is innate; the knowledge acquired. But then to what end such contest for certain innate maxims? If truths can be imprinted on the understanding without being perceived, I can see no difference there can be between any truths the mind is capable of knowing in respect of their original: they must all be innate or all adventitious: in vain shall a man go about to distinguish them. He therefore that talks of innate notions in the understanding, cannot (if he intend thereby any distinct sort of truths) mean such truths to be in the understanding as it never perceived, and is yet wholly ignorant of. For if these words "to be in the understanding" have any propriety, they signify to be understood. So that to be in the understanding, and not to be understood; to be in the mind and never to be perceived, is all one as to say anything is and is not in the mind or understanding. If therefore these two propositions, "Whatsoever is, is," and "It is impossible for the same thing to be and not to be," are by nature imprinted, children cannot be ignorant of them: infants, and all that have souls, must necessarily have them in their understandings, know the truth of them, and assent to it.

source: John Locke, An Essay Concerning Human Understanding (London: Thomas Basset, 1690): 5–6.

Scope of Locke 's Essay.

The Essay Concerning Human Understanding is divided into four books. In the first book, Locke runs through the arguments for the existence of innate ideas in order to disprove them; he calls attention to the fact that children are not born knowing the rules of logic. The second book of the Essay is the most important, for it is here that Locke presents the empiricist model of human cognition still embraced today. Locke argues that all knowledge comes through ideas, ideas being defined as the "objects" about which humans think. Introducing a metaphor still much in use, Locke pictured the human mind as a "blank page" that is filled through experience. There are two sorts of experience: "sensory," involving the acquisition of knowledge from the outside world, and "reflective," involving the manipulation within the mind of ideas already present. Likewise, there are two sorts of ideas: simple ideas having to do with the outside world that can only be received through the senses, and complex ideas that are the products of the mind's treatment and refinement of simple ideas. While humans cannot know the "essence" of things, they can come to an approximate understanding of them. Through the senses, humans can gain an idea of the primary qualities of things—their shapes, their sizes—and also the secondary qualities of things—their smell, their taste, etc. Through reflection humans can then build complex notions about things humans can then test against further sensory experiences.

Berkeley and the Christianization of Empiricism.

Although his ideas were sometimes perceived as an attack on the traditional Orthodox notion of the pervasiveness of Original Sin, Locke himself was a devout Christian who passed away while being read to from the Bible. Theologians attacked his Essay, but much of the venom of their criticism arose, not so much from Locke's work, but from the way in which his ideas were being used. In 1696, John Toland (1670–1722) published his Christianity Not Mysterious. Toland based many of his observations on the empiricist arguments in Locke's Essay, and used its reasoning to demonstrate that there was no validity at all in traditional revealed religion. Locke himself attempted to disown such a reading, but Edward Stillingfleet, the bishop of Worchester, argued after reading the Essay that it was a fair extrapolation. In a series of letters published between 1696 and 1702, Locke and Stillingfleet engaged in a polemic over whether the Essay undermined Christian faith. The point of contention was the distinction Locke insisted existed between knowledge, for which the criterion of truth had to be certainty, and faith, which by definition for Locke could only be accepted as probable. The demarcation of knowledge as something that could be only understood as true or untrue was the innovation for which Locke was being challenged. Locke was separating the understanding of the natural world and its societies from the understanding of God. As a result, he argued that the understanding of the world could be arrived at only by following empiricist procedures, while the understanding of God could never be arrived at with certainty following empiricist procedures. It was exactly upon this last point that George Berkeley (1685–1753), Anglican bishop of Cloyne in Ireland, also challenged Locke. Following Gassendi's reading of Epicurus, Locke had granted the material world a charter of independence from the spiritual world. The material world, Locke argued, could only be approached from a materialist perspective, an argument Berkeley rejected. Instead Berkeley denied the existence of a material world altogether, and denied the existence of any concrete realities outside the mind that human beings might attain some level of certainty in understanding. Whatever was out there existed solely as ideas and nothing more as they were brought within the compass of human understanding. Berkeley modified Descartes' "Cogito ergo sum" ("I think, therefore I am") to read, "Esse est percipi" ("to be is to perceive"), his point being that the one certainty humans can have is that the act of being empirical—the act of receiving information through the senses—is the validation of their conscious existence. Berkeley was a man of considerable intellectual powers. He had sufficient command of mathematics, in fact, to expose errors in Newton's calculus. It is thus significant that he turned away from science and back toward religion. His career both before and after his appointment as bishop of Cloyne can be characterized by his concern to stop what he took to be the erosion of collective belief. He identified philosophical materialism as the source of that erosion, and sought to make the case against its integrity. Berkeley's empiricism thus represented a break with the empiricism of his predecessors in that instead of attempting to free the scientific study of the physical universe from the oversight of theologians, he sought to demonstrate that whatever insights scientists gleaned about the physical universe were gifts from God. They were, in other words, signs of God's benevolence similar to the gifts the divinity had also given humankind through his revelation. In his youthful writings Berkeley had emphasized that insights about the physical universe came through the senses; now in his latter works, he articulated a Neo-Platonic position that allowed for some ideas to be innate in the human mind. Berkeley's efforts at Christianizing empiricism thus ended with a negation of the empiricist elements in his philosophy.

Condillac and Sensationism.

British empiricism had a powerful impact on intellectual thought everywhere in eighteenth-century Europe, but only one thinker on the continent made an original contribution to the empiricist school of thought. In 1688, William Molyneux, secretary to the Royal Irish Academy, sent a philosophical problem to John Locke that Molyneux hoped Locke would try his hand in solving. Suppose, Molyneux's problem began, a man born blind was trained to recognize a sphere and a cube by touch. Suppose then that this individual was granted sight. Would the individual then be able to identify a sphere and a cube by sight correctly without touching them? Locke concluded that the answer was "No." Later, when he took up the same problem, Berkeley reached the same conclusion. Both men saw this problem as turning on the issue of depth perception, and concluded, albeit with different justifications, that the circle and square that would confront the untrained eye would not immediately be recognized as a sphere and cube. Depth perception was not innate. The French empiricist Étienne Bonnot de Condillac (1714–1780), writing after Locke and Berkeley, suggested that Molyneux's problem was not about depth perception, but about the connections between the senses and the mind, and that Locke and Berkeley did not go far enough in their conclusions. To Condillac's mind, the question of depth perception took for granted that the mind was aware that there is a world outside the body where there are some things that are closer and some things that are further away. How did the mind, Condillac pondered, first come to realize that a world existed outside itself? Like Malebranche and Gassendi, Condillac was a sickly child who turned to scholarship and then to the priesthood. Condillac lived a much more varied life than either of these men, however. As a young man, he was part of an intellectual circle that included Jean-Jacques Rousseau and Denis Diderot. And for ten years of his life he served as the private tutor of the duke of Parma, the grandson of Louis XV (r. 1715–1774). Condillac's brand of empiricism has been labeled "sensationism." Sensationism moved beyond other forms of empiricism in insisting that all attributes of consciousness are the products of the senses. Whereas Locke's idea of empiricism maintained that ideas were derived from experiences, it took for granted that the mental processes through which experiences were turned into ideas were themselves innate. Condillac argued, by contrast, that mental processes were themselves the results of experience. In his Treatise on Sensations (1754) Condillac went Molyneux one better and asked his readers to imagine what would happen if an inanimate statue came to consciousness, acquiring the five senses either in isolation or in various sequences. As

THE SOURCES OF KNOWLEDGE

introduction: In his Treatise Concerning the Principles of Human Knowledge the Anglo-Irish bishop George Berkeley examined the empirical basis of human understanding. Berkeley keenly sensed some of the problems inherent in John Locke's notion of the mind as a tabula rasa. In his Treatise he outlined a thorough-going idealism—all reality is defined in the mind working in tandem with the senses. But such a commonsensical idea also had its quizzical features in Berkeley's thought. He suggested that if objects were not perceived, then they did not exist.

25. All our ideas, sensations, notions, or the things which we perceive, by whatsoever names they may be distinguished, are visibly inactive—there is nothing of power or agency included in them. So that one idea or object of thought cannot produce or make any alteration in another. To be satisfied of the truth of this, there is nothing else requisite but a bare observation of our ideas. For, since they and every part of them exist only in the mind, it follows that there is nothing in them but what is perceived: but whoever shall attend to his ideas, whether of sense or reflexion, will not perceive in them any power or activity; there is, therefore, no such thing contained in them. A little attention will discover to us that the very being of an idea implies passiveness and inertness in it, insomuch that it is impossible for an idea to do anything, or, strictly speaking, to be the cause of anything: neither can it be the resemblance or pattern of any active being, as is evident from sect. 8. Whence it plainly follows that extension, figure, and motion cannot be the cause of our sensations. To say, therefore, that these are the effects of powers resulting from the configuration, number, motion, and size of corpuscles, must certainly be false.

26. We perceive a continual succession of ideas, some are anew excited, others are changed or totally disappear. There is therefore some cause of these ideas, whereon they depend, and which produces and changes them. That this cause cannot be any quality or idea or combination of ideas, is clear from the preceding section. I must therefore be a substance; but it has been shewn that there is no corporeal or material substance: it remains therefore that the cause of ideas is an incorporeal active substance or Spirit. …

28. I find I can excite ideas in my mind at pleasure, and vary and shift the scene as oft as I think fit. It is no more than willing, and straightway this or that idea arises in my fancy; and by the same power it is obliterated and makes way for another. This making and unmaking of ideas doth very properly denominate the mind active. Thus much is certain and grounded on experience; but when we think of unthinking agents or of exciting ideas exclusive of volition, we only amuse ourselves with words.

29. But, whatever power I may have over my own thoughts, I find the ideas actually perceived by Sense have not a like dependence on my will. When in broad daylight I open my eyes, it is not in my power to choose whether I shall see or no, or to determine what particular objects shall present themselves to my view; and so likewise as to the hearing and other senses; the ideas imprinted on them are not creatures of my will. There is therefore some other Will or Spirit that produces them.

source: George Berkeley, A Treatise Concerning the Principles of Human Knowledge (1710), in The Works of George Berkeley. Vol. 1. Ed. A. C. Fraser (Oxford: Clarendon, 1910): 51–53.

Condillac saw it, the consciousness of the statue—that is, what it would know itself to be—would be a function of the combination of senses available to it. Condillac saw the human mind as passive and immobile. All it could do was react to the sensations, the impulses of data that flowed into it from the senses. Gradually, it learned to manipulate the data, to compare and contrast the latter, to arrange the latter in patterns, these acts signaling the acquisition of the mental processes earlier empiricists took as innate. As for the question of how the human mind first realized that a world existed outside itself, according to Condillac that discovery was a product of the sense of touch. Only after a human has touched an external object is it brought home to the mind that something exists that is not an extension of it.

Hume and the Secularization of Empiricism.

Meanwhile, back in Britain, Condillac's contemporary David Hume (1711–1776) was pushing empiricism in yet another direction. Like Locke, Hume was a thinker whose ideas have continued to influence the discussion of a number of topics. In the twentieth century Hume was celebrated by the philosophical naturalists, thinkers who argued that while science does not supply all the answers, its methods of investigation remain the best starting point for deriving answers. They recognized Hume as their distant forebear, an identification for which there is some justification. Hume saw himself as applying the "experimental method of reasoning" demonstrated by Newton to the "science of human nature." At the same time he has been seen as an important force that kept alive philosophical skepticism. Just as Hume reinforced the dichotomy Locke postulated between knowledge of the material world and belief in God, so Hume used Bayle's skepticism as a scalpel to slice away at the arguments through which the discussion of the physical universe had long been kept within a Christian intellectual framework. Whether Hume saw skepticism as an end in itself or merely as a tool to clear the way for his scientific philosophy remains an open question. Hume, though, more than any other figure in the empiricist movement, led the charge to secularize, that is, strip away the religious dimension from Europe's philosophical discourse. While he took up this mission in almost all his writings, the subject of all his thinking can be gleaned in his Treatise on Human Nature (1739–1740). Hume complained about the lack of public approval his treatise generated, remembering it later as having "fell dead-born from the press." So he spent the rest of his career re-packaging the ideas in the Treatise, and nowhere did he do so more effectively than in his Enquiry Concerning Human Understanding (1748). Hume recognized the twofold distinction that Locke had argued existed between sensory inputs and the mental representations they triggered. Hume labeled the former "impressions," the latter "ideas." Hume's first insight is that ideas are only "copies" of impressions. His second insight is what has been called his "liveliness" thesis: the notion that what separates ideas from impressions is the vividness of the copies. To use a modern analogy, if an image is photocopied, and then the photocopy is photocopied, each successive image will have less and less of the detail of the original. The difficulty with understanding Hume often resulted from his attacking and dismissing the "useless" ideas that he was trying to replace with his own theories. His attacks on traditional received wisdom, in other words, can be so vitriolic and entertaining that they sometimes cloud over what he had to say that was new. Using his two insights, Hume argued that all knowledge should be scrutinized to determine its factual versus its fictional character. The question concerning every idea that must be asked is "from what impression did it derive." If the source of the impression cannot be determined, Hume contends, it has no empirical validity. Hume skewered ideas concerning faith, miracles, and the supernatural because they possessed no empirical validation. Having dismissed the possibility of any spiritual basis for morality, Hume sought to establish an Epicurean notion of human ethical conduct: the pursuit of pleasure versus the avoidance of pain should be, he argued, the yardstick against which all human actions are judged. In this way, he helped to set the stage for philosophical utilitarianism in the nineteenth century.

THE IMPOSSIBILITY OF MIRACLES

introduction: In his Enquiry Concerning Human Understanding David Hume examined the long-standing claims of religion to be verified by miracles. He concluded that since miracles were violations of nature, and since experience taught that natural laws could not be violated, miracles were, in fact, impossible. His cool and detached reasoning displays one direction that Enlightenment philosophy took in the eighteenth century as it strove to prune away long-held superstitions.

A miracle is a violation of the laws of nature; and as a firm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as entire as any argument from experience can possibly be imagined. Why is it more than probable, that all men must die; that lead cannot, of itself, remain suspended in the air; that fire consumes wood, and is extinguished by water; unless it be, that these events are found agreeable to the laws of nature, and there is required a violation of these laws, or in other words, a miracle to prevent them? Nothing is esteemed a miracle, if it ever happen in the common course of nature. It is no miracle that a man, seemingly in good health, should die on a sudden: because such a kind of death, though more unusual than any other, has yet been frequently observed to happen. But it is a miracle, that a dead man should come to life; because that has never been observed in any age or country. There must, therefore, be a uniform experience against every miraculous event, otherwise the event would not merit that appellation; And as a uniform experience amounts to a proof, there is here a direct and full proof from the nature of the fact, against the existence of any miracle …

The plain consequence is (and it is a general maxim worthy of our attention), 'That no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavours to establish; and even in that case there is a mutual destruction of arguments, and the superior only gives us an assurance suitable to that degree of force, which remains after deducting the inferior.' When anyone tells me, that he saw a dead man restored to life, I immediately consider with myself, whether it be more probable, that this person should either deceive or be deceived, or that the fact, which he relates, should really have happened. I weigh the one miracle against the other; and according to the superiority, which I discover, I pronounce my decision, and always reject the greater miracle. If the falsehood of his testimony would be more miraculous, than the event which he relates; then, and not till then, can he pretend to command my belief or opinion.

In the foregoing reasoning we have supposed, that the testimony, upon which a miracle is founded, may possibly amount to an entire proof, and that the falsehood of that testimony would be a real prodigy: But it is easy to shew, that we have been a great deal too liberal in our concession, and that there never was a miraculous event established on so full an evidence.

source: David Hume, An Enquiry Concerning Human Understanding (Chicago: Open Court Publishing Co, 1926): 120–122.

sources

M. W. Cranston, John Locke: A Biography (London: Longmans, 1966).

W. Doney, Berkeley on Abstraction and Abstract Ideas (Hamden, Conn.: Garland Science Publishing, 1989).

A. C. Grayling, Berkeley: The Central Arguments (London: Duckworth, 1986).

E. C. Mossner, The Life of David Hume (Oxford: Clarendon Press, 1979).

D. F. Norton, The Cambridge Companion to Hume (Cambridge: Cambridge University Press, 1993).

J. C. O'Neal, The Authority of Experience: Sensationist Theory in the French Enlightenment (University Park, Pa.: Pennsylvania State University Press, 1996).

—, Changing Mind: The Shifting Perception of Culture in Eighteenth-Century France (Newark, Del.: University of Delaware Press, 2002).

S. Priest, The British Empiricists: Hobbes to Ayer (London: Penguin, 1990).

S. Shapin, Leviathan and the Air Pump: Hobbes, Boyle, and the Experimental Life (Princeton, N.J.: Princeton University Press, 1985).

B. S. Tinsley, Pierre Bayle's Reformation: Conscience and Criticism on the Eve of the Enlightenment (Selinsgrove, Pa.: Susquehanna University Press, 2001).

R. Whelan, The Anatomy of Superstition: A Study of the Historical Theory and Practice of Pierre Bayle (Oxford: Voltaire Foundation, 1989).