Chapter 52
Knowledge and its sources, kinds, certainty and limits; ignorance; learning.
742 passages · 215 principal · Covers the 49 volumes of primary texts
Knowledge is the idea by which every other idea is judged, for to ask about justice, God or nature is already to suppose that something can be known about them. The idea covers what knowing is and how it differs from opinion and belief, the sources from which knowing comes, the certainty it can reach and the limits it cannot pass, the ignorance that surrounds it, and the worth and dangers of the learning that pursues it. In the Harvard Classics it is a great idea because almost every author confesses some stance toward it. Philosophers take it up directly, but so do the scientist cataloguing his ignorance, the saint distrusting curiosity, the poet who makes the hunger to know a tragic passion, and the navigator who knows his position from the soundings.
The first question is what separates knowing from mere believing. Hippocrates sets knowledge, which makes a man truly know, against opinion, which leaves him ignorant1. Hobbes holds that conclusions taken on authority are only believed, not known2. Pascal observes that two readers of one book may differ, one grasping its principles and the other holding dead letters3. The Buddhist writings make the same cut between lip-profession of a doctrine and realizing it, and they test a teacher’s attainment by questioning4,5. Mill, characteristically, sets the bar highest. An opinion deserves the name of knowledge only when it has passed through controversy with opponents6. Within knowledge proper the moderns draw a further line. Hobbes divides knowledge of fact, which is sense and memory, from knowledge of consequence, which he calls science and which is only conditional7,8. Hume divides relations of ideas from matters of fact and confines demonstration to quantity and number9,10. Pascal separates subjects learned by memory and authority, such as history and theology, from those discovered by reasoning11. Freeman applies the lesson to history, which he judges less certain than mathematics or geology12. Older teachings rank knowledge by depth of insight rather than by kind of evidence. Plato holds that essences are reached by pure thought apart from the bodily organs, and fully only after death13,14. The Bhagavad-Gita grades knowledge as true, imperfect or false: true knowledge sees one changeless Life in all things, imperfect knowledge takes separate things as real, and false knowledge clings to one part as if it were the whole15.
Whence knowledge arises is the next dispute. In the Phaedo learning is recollection. We must have known absolute equality before we perceived the equal things that fall short of it, and so the soul existed before the body16,17,18. Augustine transposes this into memory and illumination. What he learns he recognizes as true within his mind, as though it were already in the heart, and learning is the gathering of what memory holds scattered19,20. Coleridge still calls learning Platonic recollection21. Against this stands the experience school. Voltaire reports Locke’s teaching that ideas enter through the senses and that human knowledge has narrow limits22. Hume challenges anyone to produce an idea without a corresponding impression, and he derives all knowledge of nature’s operations from experience23,24. Mill attacks the claim that truths external to the mind are known by intuition, which he thinks serves to prop prejudice25. Yet intuition finds defenders who owe nothing to Plato. For Emerson primary wisdom is intuition, a source behind which analysis cannot go26. Thomas à Kempis holds that God teaches inwardly, better than the schools27. Pascal adds that worldly things, once learned, are kept, whereas divine things require continuing grace28. Even Mill concedes that intuition sometimes sees truths before proof, which he can only follow29.
A practical form of the same question asks whether truth is better found for oneself or received from others. Augustine notes that history, distant places and even one’s own parentage rest on trust in testimony30, and Homer’s Telemachus knows his descent only by his mother’s word31. Descartes and Hobbes nonetheless prize self-discovery over trust in books32,33. Rousseau finds that human testimony always stands between man and God and forces endless verification34. Newman answers from the other side: books record truth, but the life and spirit of a subject are caught only from persons in whom it lives35. Ruskin asks readers to enter an author’s mind rather than seek confirmation of their own36.
Self-knowledge is offered as both the beginning and the limit of knowing. Montaigne pursues only the knowledge of himself, as the knowledge that teaches how to live and die37. Pascal calls it the best rule of life, even if it finds no truth38. Emerson fuses “Know thyself” with “Study Nature”39, and Channing holds that other minds and God are known through consciousness of one’s own soul40. The difficulty is as old as the precept. Oedipus does not see where he lives nor whence he sprang41, and Hamlet denies that anyone can pluck out the heart of his mystery42. Augustine says that man knows only part of himself and is known wholly only by God43. Pascal goes further, holding that the soul cannot know itself44, and Kant holds that we know even ourselves only as appearance45.
The moderns answer uncertainty with method. Bacon finds the state of knowledge unprosperous because the mind’s helps have been misused, and he proposes a new way for the understanding46,47. He rejects both the dogmatists who claim to know all and the sceptics who deny all, seeking instead stages of certainty48. For him human knowledge and power meet in one49, though knowledge is to be sought for the use of life and governed in charity50. Descartes found that his schooling gave no certain knowledge51 and trusted an order of deduction by which nothing knowable lies beyond reach52. Rousseau’s Vicar enters Cartesian doubt and finds it disquieting53. A different test of knowledge is social rather than solitary. Newman holds that inquiry advances and error is exposed by the collision of mind with mind54. Mill holds that he who knows only his own side knows little even of that55. Milton calls opinion in good men knowledge in the making56.
Scepticism presses hardest on these hopes. Pascal argues that we cannot prove we are not dreaming57, and that our condition makes both certain knowledge and absolute ignorance impossible to us58. Yet he insists that no one is a complete sceptic59, and that the dream argument shows the weakness of reason rather than the uncertainty of all knowledge60. Hume, too, judges universal Cartesian doubt incurable and finds that neither instinct nor reason secures belief in external objects61,62. His remedy is a mitigated scepticism confined to common life and experience63. Berkeley lets Hylas declare that we know only our ideas and that ignorance is the perfection of human knowledge64. Philonous replies that this deepest scepticism springs from the groundless hypothesis of unknown originals, and that to know the nature of things is to know which ideas are connected65,66,67. Kant draws the boundary that the others only approach. We know appearances, not things in themselves; we have an idea of the intelligible world but no knowledge of it; and all explanation stops at its threshold45,68,69. Others fix assurance in action rather than in theory. Carlyle holds that doubt is inexhaustible and that certainty comes only by doing70. Mill grounds his liberty on a fallibility that men admit in theory but rarely act upon71. Even the ancient Phaedo counsels taking the best human doctrine as a raft72.
Ignorance is the shadow that accompanies knowledge everywhere. Confucius defines understanding as knowing what one knows and what one does not73, and Socrates’ slight advantage lies in knowing his ignorance74. The Buddhist monk demands that the Buddha either declare what he knows or honestly confess that he does not know75. Browne holds that the truly capable know they know nothing76, and Pascal distinguishes the learned ignorance that meets natural ignorance from the pretension of the half-learned77. Confession of ignorance about nature runs from Herodotus, who could learn nothing of why the Nile rises78, to Darwin’s repeated admissions of profound ignorance of variation and of the mutual relations of living beings79,80. Darwin adds that the chief objections to his theory concern matters of confessed ignorance, and that we do not know how ignorant we are81. Pascal states the principle: a part cannot know the whole, and parts cannot be known without the whole82. Hume reaches a conclusion of human blindness83, and Pope says that Newton cannot explain his own mind84. Ignorance is also the source of evil. Epictetus and Marcus Aurelius trace all wrongdoing to ignorance of good and evil85,86. Buddhism makes ignorance of the Four Truths the dependence of karma87. Hobbes finds that ignorance of causes breeds credulity and reliance on authority88,89. Worst is ignorance that thinks it knows: Epictetus says the conceit of knowledge blocks learning90. Bunyan’s character Ignorance trusts the testimony of his heart91, and Thoreau calls much so-called knowledge positive ignorance92.
Of God the limits are sharpest. Job’s God exposes man’s ignorance of creation, and Ecclesiastes says no one can find out the work done under the sun93,94. Dante shows Plato and Aristotle desiring fruitlessly what lies beyond reason, and holds that even a seraph cannot fathom Providence95,96. Milton’s angel warns that God conceals high things97. The remedy is revelation. Paul teaches that the natural man cannot know divine things, which are known only through the Spirit98. Calvin holds that knowledge of the Creator is innate but corrupted, so that Scripture is needed99, and Pascal that we know God and ourselves only through Christ100. Divine knowledge is contrasted throughout with human knowing. For the Psalmist God’s knowledge of every thought is too wonderful to attain101. For Browne what are probabilities to us are demonstrations to angels102, and for Rousseau God knows by intuition, without reasoning103.
The worth of learning is praised and doubted in nearly equal measure. Hobbes calls the desire to know causes a lust of the mind whose delight exceeds carnal pleasure104. Locke treats curiosity as an appetite that removes innate ignorance105, and Dante’s thirst grows as it is satisfied106. Bacon’s island trades for nothing but Light107. Milton defends books on the ground that knowledge cannot defile where will and conscience are pure108, and he warns that suppression would bring a famine on minds109. Against such praise stands Paul’s warning that knowledge puffs up but love edifies110, echoed by Augustine and Thomas à Kempis111,112. Sidney names well-doing, not well-knowing, as the end of learning113, and Euripides locates sorrow in the failure to act on what one knows to be right114. Tennyson compresses the point: knowledge comes, but wisdom lingers115. The tragic version is forbidden knowledge. Milton’s Tree is knowledge of good bought dear by knowing ill, and Adam learns that to aspire beyond what he can hold was folly116,117. Marlowe’s Faustus finds every science insufficient and ends wishing he had never read a book118,119. Goethe’s Faust turns to magic because book learning yields nothing certain120. Byron’s Manfred finds that sorrow is knowledge and that the Tree of Knowledge is not the Tree of Life121. Yet Tennyson’s Ulysses still follows knowledge like a sinking star122, and Browning’s grammarian chooses to Know rather than Live123. A humbler danger is shallow learning. Montaigne requires that knowledge be digested like food124, Channing denies that book-learning is intellectual improvement125, and Carlyle tells students to count a thing known only when it is clearly grasped126.
Several questions remain open across these books. The ancients locate the source of knowledge within the soul or in a divine light, while the moderns test it against sense, method and controversy. Berkeley and Kant refuse the scepticism that Hume could only mitigate, but in opposite ways. Whether knowledge is the soul’s food or its temptation, Milton himself answers in two voices. Bacon’s union of knowledge with power is shadowed by Faust and Manfred. And Darwin’s confession that we do not know how ignorant we are leaves the Socratic beginning where it was, at the edge of every advance.
Introductory essay written by Claude Opus 5.5 from the outline and the notes on every passage below; quotations are checked against this edition.
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See also: Memory and Imagination 2a
See also: Opinion 10b
See also: Reasoning 7b
See also: Sense 3b · Matter 5c
See also: Liberty 1b · Will 1b
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See also: God 2a
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See also: Opinion 10a · Liberty 5a · Censorship 2d · Truth 5a
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See also: Desire 10a · Sin 2b
See also: Education, Philosophy, Wisdom, God, Man, Reasoning