An Enquiry Concerning Human Understanding by David Hume

First published: 1748

Type of work: Philosophy

The Work:

“Philosophical decisions,” says David Hume toward the end of his An Enquiry Concerning Human Understanding, “are nothing but the reflections of common life, methodised and corrected.” This simple, homely epigram conceals a great deal. For one thing, An Enquiry Concerning Human Understanding is actually a sort of popularized revision of ideas that were systematically developed in book 1 of his precocious A Treatise of Human Nature (1739-1740), which, although it was completed before the author was twenty-five, has been characterized as one of the most profound, thoroughly reasoned, and purely scientific works in the history of philosophy. Second, Hume’s method for correcting the reflections of common life actually involves a thorough attack on the obscurities of metaphysical idealists.

Born in an age of reason, Hume at first shared the optimism of those who were certain that pure reason could unlock the secrets of nature, and as he read Francis Bacon, John Newton, Thomas Hobbes, and John Locke, he longed for fame equal to theirs. However, as he reported in a letter to Sir Gilbert Elliot, although he “began with an anxious search after arguments, to confirm the common opinion; doubts stole in, dissipated, returned; were again dissipated, returned again; and it was a perpetual struggle of restless imagination against inclination, perhaps against reason.” That last, “perhaps against reason,” is the crucial phrase, for no philosopher before Hume used reason so brilliantly in an attack against the certainties of reason. The twelve essays of An Enquiry Concerning Human Understanding reflect Hume’s three principal attacks against rationalism: against the doctrine of innate ideas and faith in ontological reasoning and an ordered universe; against empiricism, both the kind that led to Lockean dualism and the kind that led to Berkeleyan idealism, on the ground that neither the physical nor the spiritual can be proved; and against deism, based on universal axioms and the law of causality. It is not surprising that religions since Hume have largely made their appeals to faith rather than to reason.

Considering what remains when such thoroughgoing skepticism rejects so much of the beliefs of rational human beings, Hume himself readily admitted (in the fourth essay, “Sceptical Doubts Concerning the Operations of the Understanding”) that as a man he was quite satisfied with ordinary reasoning processes but that as a philosopher he had to be skeptical, for reasoning was not based on immediate sense experience. “The most lively thought is still inferior to the dullest sensation,” he asserted in his second essay, “The Origin of Ideas.” Unless the mind is “disordered by disease or madness,” actual perceptions have the greatest “force and vivacity,” and it is only on such matters of basic mental fact rather than on the abstract relations of ideas, as in mathematics, that human beings must depend for certainties about life. No amount of reasoning, for example, could have led Adam in the Garden of Eden to believe that fluid, transparent water would drown him or that bright, warm fire would burn him to ashes. “No object ever discovers, by the qualities which appear to the senses, either the causes which produced it, or the effects which arise from it.” In dealing with this idea, Hume doggedly backs every argument into a corner, into some “dangerous dilemma.” What is more, he enjoys himself immensely while doing it—“philosophers that gave themselves airs of superior wisdom and sufficiency, have a hard task when they encounter persons of inquisitive dispositions,” he says. Concerning cause and effect, he argues that similar effects are expected from causes that appear similar, yet this relationship does not always exist and, even when observed, is not reasoned. Furthermore, it is merely an arbitrary assumption, an act of faith, that events that are remembered as having occurred sequentially in the past will continue to do so in the future. Causation thus was merely a belief, a belief he defined as a “lively idea related to or associated with a present impression.”

This seemed to Hume not merely an impractical philosophical idea, but a momentous discovery of great consequence. Since causation was an a priori principle of both natural and moral philosophy, and since causation could not be reasonably demonstrated to be true, a tremendous revolution in human thought was in preparation. Only in the pure realm of ideas, logic, and mathematics, not contingent on the direct sense awareness of reality, could causation safely (because arbitrarily) be applied—all other sciences are reduced to probability. The concluding essay, “Of the Academical or Sceptical Philosophy,” reaches grand heights of eloquence when Hume argues that a priori reasoning can make anything appear to produce anything: “the falling of a pebble may, for aught we know, extinguish the sun; or the wish of a man control the planets in their orbits.”

When we run over libraries, persuaded of these principles, what havoc must we make? If we take in hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.

The polemic vigor of the essays stems in large part from the bitter experiences Hume had in the years immediately preceding the publication of An Enquiry Concerning Human Understanding. In 1744, he had sought to fill a vacancy in the chair of ethics and pneumatical philosophy at Edinburgh University, but to his astonishment his ATreatise of Human Nature was invoked to prevent the appointment: “such a popular clamor has been raised against me in Edinburgh, on account of Scepticism, Heterodoxy, and other hard names . . . that my Friends find some Difficulty in working out the Point of my Professorship.” Then he was dismissed without full salary as tutor to the mad son of the marquis of Annandale. These experiences played a part in sharpening the cutting edge of his thought and prose style.

After refining his conception of reason and its modes of function, Hume applies it to four crucial problems: “Liberty and Necessity,” “Reason of Animals,” “Miracles,” and “Particular Providence and a Future State.” Concerning the first, Hume argues that since the subject relates to common life and experience (unlike such topics as the origin of worlds or the region of spirits), only ambiguity of language keeps the dispute alive. For a clear definition, he suggests that it be consistent with plain matters of fact and with itself. Difficulty arises when philosophers approach the problem by examining the faculties of the soul rather than the operations of body and brute matter. In the latter, people assume that they perceive cause and effect, but in the functioning of their minds they feel no connection between motive and action. However, the doctrine of cause and effect cannot be invoked without, ultimately, tracing all actions—including evil ones—to the deity whom people refuse to accept as the author of guilt and moral turpitude in all creatures. As a matter of fact, freedom and necessity are matters of momentary emotional feeling “not to be controuled or altered by any philosophical theory or speculation whatsoever.”

The reason of animals, according to Hume, consists—as it does in children, philosophers, and humankind in general—not so much in logical inferences as in experience of analogies and sequential actions. Observation and experience alone teach a horse the proper height that he can leap or a greyhound how to meet the hare in her tracks with the least expenditure of energy. Hume’s learning theory here seems to be based on the pleasure-pain principle and forms the background for certain theories of twentieth century psychology. However, Hume ends this essay with a long qualification in which he cites the “Instincts,” unlearned knowledge derived from the original hand of nature, and then adds this curious final comment: “The experimental reasoning itself, which we possess in common with beasts, and on which the whole conduct of life depends, is nothing but a species of instinct or mechanical power, that acts in us unknown to ourselves.”

The essay on miracles is perhaps the most spirited of the entire collection, and it is the one that Hume expected, correctly, would stir the greatest opposition. Nevertheless, he was certain that his argument would be for the wise and the learned “an everlasting check to all kinds of superstitious delusion, and consequently . . . useful as long as the world endures.” Events can be believed to happen only when they are observed, and all reports of events not directly observed must be believed only to the degree that they conform with probability, experimentally or experientially derived. A miracle is a violation of the laws of nature; therefore it violates all probability; therefore it is impossible. History gives no instance of any miracle observed by a sufficient number of unquestionably honest, educated, intelligent individuals. Despite the surprise, wonder, and other pleasant sensations attendant upon reports of novel experiences, all new discoveries that achieve credibility among people have always resembled in fundamentals those objects and events that have already been experienced. The most widespread belief in miracles exists among so-called primitive peoples. Finally, since there is no objective way of confirming miracles, believers have no just basis for rejecting those claimed by all religions. “So that, on the whole, we may conclude, that the Christian Religion not only was at first attended with miracles, but even at this day cannot be believed by any reasonable person without one. Mere reason is insufficient to convince us . . . to believe what is most contrary to custom and experience.”

In the 1777 posthumous edition of An Enquiry Concerning Human Understanding appeared the announcement that these unsystematic essays should be regarded only as containing Hume’s philosophical sentiments and principles. Although professional philosophers, especially the logical positivists, still prefer Hume’s earlier Treatise of Human Nature, it is An Enquiry Concerning Human Understanding, with its livelier style and popular appeal, that stands as his personal testament. In it he said that he would be “happy if . . . we can undermine the foundations of an abstruse philosophy, which seems to have hitherto served only as a shelter to superstition, and a cover to absurdity and error.” The irony is that he succeeded so well in undermining reason that he opened the door to the Romanticism of the late eighteenth and early nineteenth centuries. His voice has, however, outlasted that babel and his humanistic skepticism survives. “Be a philosopher,” he cautioned himself, “but amidst all your philosophy, be still a man.”

Bibliography

Bailey, Alan, and Daniel O’Brien. Hume’s “Enquiry Concerning Human Understanding”: Reader’s Guide. London: Continuum, 2006. Introductory overview, aimed at undergraduate students and general readers. Discusses the philosophical background, key themes and concepts, critical reception, and influence of Hume’s work.

Buckle, Stephen. Hume’s Enlightenment Tract: The Unity and Purpose of “An Enquiry Concerning Human Understanding.” New York: Oxford University Press, 2001. A commentary on An Enquiry Concerning Human Understanding by a leading Hume scholar. Buckle explicates Hume’s arguments and places the work within its historical and intellectual context and its relationship to Enlightenment thought.

Noxon, James. Hume’s Philosophical Development. Oxford, England: Clarendon Press, 1973. Compares Hume’s A Treatise of Human Nature and An Enquiry Concerning Human Understanding.

Olshewsky, Thomas M. “The Classical Roots of Hume’s Skepticism.” Journal of the History of Ideas 52, no. 2 (April-June, 1991): 269-288. Interprets Hume’s work through an analysis of skepticism on the basis of the Stoic philosophy of Sextus Empiricus.

Radcliffe, Elizabeth S., ed. A Companion to Hume. Malden, Mass.: Blackwell, 2008. Collection of twenty-eight essays interpreting the various aspects of Hume’s philosophy. The numerous references to An Enquiry Concerning Human Understanding are listed in the index.

Read, Rupert, and Kenneth A. Richman, eds. The New Hume Debate. Rev. ed. New York: Routledge, 2007. The “debate” concerns Hume’s ideas about the existence of causes and objects. Traditionally, scholars considered him to be a skeptic regarding these matters, but many modern critics now regard him as a “skeptical realist.” This collection ofessays provides various interpretations of the “new Hume,” with numerous references to An Enquiry Concerning Human Understanding.

Stumpf, Samuel E. Philosophy: History and Problems. New York: McGraw-Hill, 1977. Stumpf’s chapter on empiricism in Britain is one of the clearest explanations of the issues and responses that form the context of the philosophies of a trio of thinkers—John Locke, George Berkeley, and Hume. An understanding of the first two is essential to grasping the importance of Hume’s An Enquiry Concerning Human Understanding.