Henry David Thoreau (see name pronunciation; July 12, 1817 – May 6, 1862) was an American essayist, poet, philosopher, abolitionist, naturalist, tax resister, development critic, surveyor, and historian. A leading transcendentalist, Thoreau is best known for his book Walden, a reflection upon simple living in natural surroundings, and his essay "Civil Disobedience" (originally published as "Resistance to Civil Government"), an argument for disobedience to an unjust state.
Thoreau's books, articles, essays, journals, and poetry amount to more than 20 volumes. Among his lasting contributions are his writings on natural history and philosophy, in which he anticipated the methods and findings of ecology and environmental history, two sources of modern-day environmentalism. His literary style interweaves close observation of nature, personal experience, pointed rhetoric, symbolic meanings, and historical lore, while displaying a poetic sensibility, philosophical austerity, and Yankee attention to practical detail. He was also deeply interested in the idea of survival in the face of hostile elements, historical change, and natural decay; at the same time he advocated abandoning waste and illusion in order to discover life's true essential needs.
He was a lifelong abolitionist, delivering lectures that attacked the Fugitive Slave Law while praising the writings of Wendell Phillips and defending the abolitionist John Brown. Thoreau's philosophy of civil disobedience later influenced the political thoughts and actions of such notable figures as Leo Tolstoy, Mahatma Gandhi, and Martin Luther King Jr.
Thoreau is sometimes referred to as an anarchist. Though "Civil Disobedience" seems to call for improving rather than abolishing government—"I ask for, not at once no government, but at once a better government"—the direction of this improvement points toward anarchism: "'That government is best which governs not at all;' and when men are prepared for it, that will be the kind of government which they will have."
Amos Bronson Alcott and Thoreau's aunt each wrote that "Thoreau" is pronounced like the word thorough (pronounced thur-oh—/ˈθʌroʊ/—in General American, but more precisely thor-oh—/ˈθɔːroʊ/—in 19th-century New England). Edward Waldo Emerson wrote that the name should be pronounced "Thó-row", with the h sounded and stress on the first syllable. Among modern-day American speakers, it is perhaps more commonly pronounced thə-roh—/θəˈroʊ/—with stress on the second syllable.
Thoreau was a homely man, with a nose that he called "my most prominent feature." Of his appearance and disposition, Ellery Channing wrote, "His face, once seen, could not be forgotten. The features were quite marked: the nose aquiline or very Roman, like one of the portraits of Caesar (more like a beak, as was said); large overhanging brows above the deepest set blue eyes that could be seen, in certain lights, and in others gray,—eyes expressive of all shades of feeling, but never weak or near-sighted; the forehead not unusually broad or high, full of concentrated energy and purpose; the mouth with prominent lips, pursed up with meaning and thought when silent, and giving out when open with the most varied and unusual instructive sayings."
Henry David Thoreau was born David Henry Thoreau in Concord, Massachusetts, into the "modest New England family" of John Thoreau, a pencil maker, and Cynthia Dunbar. His paternal grandfather was born in Jersey. His maternal grandfather, Asa Dunbar, led Harvard's 1766 student "Butter Rebellion", the first recorded student protest in the American colonies. David Henry was named after his recently deceased paternal uncle, David Thoreau. He began to call himself Henry David after he finished college; he never petitioned to make a legal name change. He had two older siblings, Helen and John Jr., and a younger sister, Sophia. Thoreau's birthplace still exists on Virginia Road in Concord. The house has been restored by the Thoreau Farm Trust, a nonprofit organization, and is now open to the public.
He studied at Harvard College between 1833 and 1837. He lived in Hollis Hall and took courses in rhetoric, classics, philosophy, mathematics, and science. He was a member of the Institute of 1770 (now the Hasty Pudding Club). According to legend, Thoreau refused to pay the five-dollar fee for a Harvard diploma. In fact, the master's degree he declined to purchase had no academic merit: Harvard College offered it to graduates "who proved their physical worth by being alive three years after graduating, and their saving, earning, or inheriting quality or condition by having Five Dollars to give the college." He commented, "Let every sheep keep its own skin", a reference to the tradition of using sheepskin vellum for diplomas.
The traditional professions open to college graduates—law, the church, business, medicine—did not interest Thoreau,:25 so in 1835 he took a leave of absence from Harvard, during which he taught school in Canton, Massachusetts. After he graduated in 1837, he joined the faculty of the Concord public school, but he resigned after a few weeks rather than administer corporal punishment.:25 He and his brother John then opened the Concord Academy, a grammar school in Concord in 1838.:25 They introduced several progressive concepts, including nature walks and visits to local shops and businesses. The school closed when John became fatally ill from tetanus in 1842 after cutting himself while shaving. He died in Henry's arms.
Upon graduation Thoreau returned home to Concord, where he met Ralph Waldo Emerson through a mutual friend. Emerson took a paternal and at times patronizing interest in Thoreau, advising the young man and introducing him to a circle of local writers and thinkers, including Ellery Channing, Margaret Fuller, Bronson Alcott, and Nathaniel Hawthorne and his son Julian Hawthorne, who was a boy at the time.
Emerson urged Thoreau to contribute essays and poems to a quarterly periodical, The Dial, and lobbied the editor, Margaret Fuller, to publish those writings. Thoreau's first essay published in The Dial was "Aulus Persius Flaccus," an essay on the Roman playwright, in July 1840. It consisted of revised passages from his journal, which he had begun keeping at Emerson's suggestion. The first journal entry, on October 22, 1837, reads, "'What are you doing now?' he asked. 'Do you keep a journal?' So I make my first entry to-day."
Thoreau was a philosopher of nature and its relation to the human condition. In his early years he followed Transcendentalism, a loose and eclectic idealist philosophy advocated by Emerson, Fuller, and Alcott. They held that an ideal spiritual state transcends, or goes beyond, the physical and empirical, and that one achieves that insight via personal intuition rather than religious doctrine. In their view, Nature is the outward sign of inward spirit, expressing the "radical correspondence of visible things and human thoughts", as Emerson wrote in Nature (1836).
On April 18, 1841, Thoreau moved into the Emerson house. There, from 1841 to 1844, he served as the children's tutor; he was also an editorial assistant, repairman and gardener. For a few months in 1843, he moved to the home of William Emerson on Staten Island, and tutored the family's sons while seeking contacts among literary men and journalists in the city who might help publish his writings, including his future literary representative Horace Greeley.:68
Thoreau returned to Concord and worked in his family's pencil factory, which he continued to do for most of his adult life. He rediscovered the process of making good pencils with inferior graphite by using clay as the binder; this invention improved upon graphite found in New Hampshire and bought in 1821 by a relative, Charles Dunbar. (The process of mixing graphite and clay, known as the Conté process, was patented by Nicolas-Jacques Conté in 1795.) His other source had been Tantiusques, a mine operated by Native Americans in Sturbridge, Massachusetts. Later, Thoreau converted the factory to produce plumbago (graphite), which was used in the electrotyping process.
Once back in Concord, Thoreau went through a restless period. In April 1844 he and his friend Edward Hoar accidentally set a fire that consumed 300 acres (1.2 km2) of Walden Woods.
I went to the woods because I wished to live deliberately, to front only the essential facts of life, and see if I could not learn what it had to teach, and not, when I came to die, discover that I had not lived. I did not wish to live what was not life, living is so dear; nor did I wish to practise resignation, unless it was quite necessary. I wanted to live deep and suck out all the marrow of life, to live so sturdily and Spartan-like as to put to rout all that was not life, to cut a broad swath and shave close, to drive life into a corner, and reduce it to its lowest terms, and, if it proved to be mean, why then to get the whole and genuine meanness of it, and publish its meanness to the world; or if it were sublime, to know it by experience, and be able to give a true account of it in my next excursion.— Henry David Thoreau, "Where I Lived, and What I Lived For", in Walden
Thoreau felt a need to concentrate and work more on his writing. In March 1845, Ellery Channing told Thoreau, "Go out upon that, build yourself a hut, & there begin the grand process of devouring yourself alive. I see no other alternative, no other hope for you." Two months later, Thoreau embarked on a two-year experiment in simple living on July 4, 1845, when he moved to a small house he had built on land owned by Emerson in a second-growth forest around the shores of Walden Pond. The house was in "a pretty pasture and woodlot" of 14 acres (57,000 m2) that Emerson had bought, 1.5 miles (2.4 km) from his family home.
On July 24 or July 25, 1846, Thoreau ran into the local tax collector, Sam Staples, who asked him to pay six years of delinquent poll taxes. Thoreau refused because of his opposition to the Mexican–American War and slavery, and he spent a night in jail because of this refusal. The next day Thoreau was freed when someone, likely to have been his aunt, paid the tax, against his wishes. The experience had a strong impact on Thoreau. In January and February 1848, he delivered lectures on "The Rights and Duties of the Individual in relation to Government", explaining his tax resistance at the Concord Lyceum. Bronson Alcott attended the lecture, writing in his journal on January 26:
Heard Thoreau's lecture before the Lyceum on the relation of the individual to the State—an admirable statement of the rights of the individual to self-government, and an attentive audience. His allusions to the Mexican War, to Mr. Hoar's expulsion from Carolina, his own imprisonment in Concord Jail for refusal to pay his tax, Mr. Hoar's payment of mine when taken to prison for a similar refusal, were all pertinent, well considered, and reasoned. I took great pleasure in this deed of Thoreau's.— Bronson Alcott, , Journals
Thoreau revised the lecture into an essay entitled "Resistance to Civil Government" (also known as "Civil Disobedience"). It was published by Elizabeth Peabody in the Aesthetic Papers in May 1849. Thoreau had taken up a version of Percy Shelley's principle in the political poem "The Mask of Anarchy" (1819), which begins with the powerful images of the unjust forms of authority of his time and then imagines the stirrings of a radically new form of social action.
At Walden Pond, Thoreau completed a first draft of A Week on the Concord and Merrimack Rivers, an elegy to his brother John, describing their trip to the White Mountains in 1839. Thoreau did not find a publisher for the book and instead printed 1,000 copies at his own expense; fewer than 300 were sold.:234 He self-published the book on the advice of Emerson, using Emerson's publisher, Munroe, who did little to publicize the book.
In August 1846, Thoreau briefly left Walden to make a trip to Mount Katahdin in Maine, a journey later recorded in "Ktaadn", the first part of The Maine Woods.
Thoreau left Walden Pond on September 6, 1847.:244 At Emerson's request, he immediately moved back to the Emerson house to help Emerson's wife, Lidian, manage the household while her husband was on an extended trip to Europe. Over several years, as he worked to pay off his debts, he continuously revised the manuscript of what he eventually published as Walden, or Life in the Woods in 1854, recounting the two years, two months, and two days he had spent at Walden Pond. The book compresses that time into a single calendar year, using the passage of the four seasons to symbolize human development. Part memoir and part spiritual quest, Walden at first won few admirers, but later critics have regarded it as a classic American work that explores natural simplicity, harmony, and beauty as models for just social and cultural conditions.
The American poet Robert Frost wrote of Thoreau, "In one book ... he surpasses everything we have had in America."
The American author John Updike said of the book, "A century and a half after its publication, Walden has become such a totem of the back-to-nature, preservationist, anti-business, civil-disobedience mindset, and Thoreau so vivid a protester, so perfect a crank and hermit saint, that the book risks being as revered and unread as the Bible."
Thoreau moved out of Emerson's house in July 1848 and stayed at a house on nearby Belknap Street. In 1850, he and his family moved into a house at 255 Main Street, where he lived until his death.
In 1851, Thoreau became increasingly fascinated with natural history and narratives of travel and expedition. He read avidly on botany and often wrote observations on this topic into his journal. He admired William Bartram and Charles Darwin's Voyage of the Beagle. He kept detailed observations on Concord's nature lore, recording everything from how the fruit ripened over time to the fluctuating depths of Walden Pond and the days certain birds migrated. The point of this task was to "anticipate" the seasons of nature, in his word.
He became a land surveyor and continued to write increasingly detailed observations on the natural history of the town, covering an area of 26 square miles (67 km2), in his journal, a two-million-word document he kept for 24 years. He also kept a series of notebooks, and these observations became the source of his late writings on natural history, such as "Autumnal Tints", "The Succession of Trees", and "Wild Apples", an essay lamenting the destruction of indigenous wild apple species.
Until the 1970s, literary critics[who?] dismissed Thoreau's late pursuits as amateur science and philosophy. With the rise of environmental history and ecocriticism as academic disciplines, several new readings of Thoreau began to emerge, showing him to have been both a philosopher and an analyst of ecological patterns in fields and woodlots. For instance, his late essay "The Succession of Forest Trees" shows that he used experimentation and analysis to explain how forests regenerate after fire or human destruction, through the dispersal of seeds by winds or animals.
He traveled to Quebec once, Cape Cod four times, and Maine three times; these landscapes inspired his "excursion" books, A Yankee in Canada, Cape Cod, and The Maine Woods, in which travel itineraries frame his thoughts about geography, history and philosophy. Other travels took him southwest to Philadelphia and New York City in 1854 and west across the Great Lakes region in 1861, when he visited Niagara Falls, Detroit, Chicago, Milwaukee, St. Paul and Mackinac Island. He was provincial in his own travels, but he read widely about travel in other lands. He devoured all the first-hand travel accounts available in his day, at a time when the last unmapped regions of the earth were being explored. He read Magellan and James Cook; the arctic explorers John Franklin, Alexander Mackenzie and William Parry; David Livingstone and Richard Francis Burton on Africa; Lewis and Clark; and hundreds of lesser-known works by explorers and literate travelers. Astonishing amounts of reading fed his endless curiosity about the peoples, cultures, religions and natural history of the world and left its traces as commentaries in his voluminous journals. He processed everything he read, in the local laboratory of his Concord experience. Among his famous aphorisms is his advice to "live at home like a traveler."
After John Brown's raid on Harpers Ferry, many prominent voices in the abolitionist movement distanced themselves from Brown or damned him with faint praise. Thoreau was disgusted by this, and he composed a key speech, A Plea for Captain John Brown, which was uncompromising in its defense of Brown and his actions. Thoreau's speech proved persuasive: the abolitionist movement began to accept Brown as a martyr, and by the time of the American Civil War entire armies of the North were literally singing Brown's praises. As a biographer of Brown put it, "If, as Alfred Kazin suggests, without John Brown there would have been no Civil War, we would add that without the Concord Transcendentalists, John Brown would have had little cultural impact."
Thoreau contracted tuberculosis in 1835 and suffered from it sporadically afterwards. In 1860, following a late-night excursion to count the rings of tree stumps during a rainstorm, he became ill with bronchitis. His health declined, with brief periods of remission, and he eventually became bedridden. Recognizing the terminal nature of his disease, Thoreau spent his last years revising and editing his unpublished works, particularly The Maine Woods and Excursions, and petitioning publishers to print revised editions of A Week and Walden. He wrote letters and journal entries until he became too weak to continue. His friends were alarmed at his diminished appearance and were fascinated by his tranquil acceptance of death. When his aunt Louisa asked him in his last weeks if he had made his peace with God, Thoreau responded, "I did not know we had ever quarreled."
Aware he was dying, Thoreau's last words were "Now comes good sailing", followed by two lone words, "moose" and "Indian". He died on May 6, 1862, at age 44. Bronson Alcott planned the service and read selections from Thoreau's works, and Channing presented a hymn. Emerson wrote the eulogy spoken at the funeral. Thoreau was buried in the Dunbar family plot; his remains and those of members of his immediate family were eventually moved to Sleepy Hollow Cemetery () in Concord, Massachusetts.
Thoreau's friend Ellery Channing published his first biography, Thoreau the Poet-Naturalist, in 1873. Channing and another friend, Harrison Blake, edited some poems, essays, and journal entries for posthumous publication in the 1890s. Thoreau's journals, which he often mined for his published works but which remained largely unpublished at his death, were first published in 1906 and helped to build his modern reputation. A new, expanded edition of the journals is under way, published by Princeton University Press. Today, Thoreau is regarded as one of the foremost American writers, both for the modern clarity of his prose style and the prescience of his views on nature and politics. His memory is honored by the international Thoreau Society and his by the Thoreau Institute at Walden Woods, established in 1998 in Lincoln, Massachusetts.
Most of the luxuries and many of the so-called comforts of life are not only not indispensable, but positive hindrances to the elevation of mankind.— Thoreau
Thoreau was an early advocate of recreational hiking and canoeing, of conserving natural resources on private land, and of preserving wilderness as public land. He was himself a highly skilled canoeist; Nathaniel Hawthorne, after a ride with him, noted that "Mr. Thoreau managed the boat so perfectly, either with two paddles or with one, that it seemed instinct with his own will, and to require no physical effort to guide it." 
He was not a strict vegetarian, though he said he preferred that diet and advocated it as a means of self-improvement. He wrote in Walden, "The practical objection to animal food in my case was its uncleanness; and besides, when I had caught and cleaned and cooked and eaten my fish, they seemed not to have fed me essentially. It was insignificant and unnecessary, and cost more than it came to. A little bread or a few potatoes would have done as well, with less trouble and filth."
Thoreau neither rejected civilization nor fully embraced wilderness. Instead he sought a middle ground, the pastoral realm that integrates nature and culture. His philosophy required that he be a didactic arbitrator between the wilderness he based so much on and the spreading mass of humanity in North America. He decried the latter endlessly but felt that a teacher needs to be close to those who needed to hear what he wanted to tell them. The wildness he enjoyed was the nearby swamp or forest, and he preferred "partially cultivated country." His idea of being "far in the recesses of the wilderness" of Maine was to "travel the logger's path and the Indian trail", but he also hiked on pristine land. In the essay "Henry David Thoreau, Philosopher" Roderick Nash wrote, "Thoreau left Concord in 1846 for the first of three trips to northern Maine. His expectations were high because he hoped to find genuine, primeval America. But contact with real wilderness in Maine affected him far differently than had the idea of wilderness in Concord. Instead of coming out of the woods with a deepened appreciation of the wilds, Thoreau felt a greater respect for civilization and realized the necessity of balance." Of alcohol, Thoreau wrote, "I would fain keep sober always.... I believe that water is the only drink for a wise man; wine is not so noble a liquor.... Of all ebriosity, who does not prefer to be intoxicated by the air he breathes?"
Thoreau never married and was childless. He strove to portray himself as an ascetic puritan. However, his sexuality has long been the subject of speculation, including by his contemporaries. Critics have called him heterosexual, homosexual, or asexual. There is no evidence to suggest he had physical relations with anyone, man or woman. Some scholars have suggested that homoerotic sentiments run through his writings and concluded that he was homosexual. The elegy Sympathy was inspired by the eleven-year-old Edmund Sewell, with whom he hiked for five days in 1839. One scholar has suggested that he wrote the poem to Edmund because he could not bring himself to write it to Edmund's sister, and another that Thoreau's "emotional experiences with women are memorialized under a camouflage of masculine pronouns", but other scholars dismiss this. It has argued that the long paean in Walden to the French-Canadian woodchopper Alek Therien, which includes allusions to Achilles and Patroclus, is an expression of conflicted desire. In some of Thoreau's writing there is the sense of a secret self. In 1840 he writes in his journal: "My friend is the apology for my life. In him are the spaces which my orbit traverses". Thoreau was strongly influenced by the moral reformers of his time, and this may have instilled anxiety and guilt over sexual desire.
Thoreau was fervently against slavery and actively supported the abolitionist movement. He participated in the Underground Railroad, delivered lectures that attacked the Fugitive Slave Law, and in opposition with the popular opinion of the time, supported radical abolitionist militia leader John Brown and his party. Two weeks after the ill-fated raid on Harpers Ferry and in the weeks leading up to Brown's execution, Thoreau regularly delivered a speech to the citizens of Concord, Massachusetts in which he compared the American government to Pontius Pilate and likened Brown's execution to the crucifixion of Jesus Christ:
"Some eighteen hundred years ago Christ was crucified; this morning, perchance, Captain Brown was hung. These are the two ends of a chain which is not without its links. He is not Old Brown any longer; he is an angel of light."
In The Last Days of John Brown, Thoreau described the words and deeds of John Brown as noble and an example of heroism. In addition, he lamented the newspaper editors who dismissed Brown and his scheme as "crazy".
Thoreau was a proponent of limited government and individualism. Although he was hopeful that mankind could potentially have, through self-betterment, the kind of government which "governs not at all", he distanced himself from contemporary "no-government men" (anarchists), writing: "I ask for, not at once no government, but at once a better government."
Thoreau deemed the evolution from absolute monarchy to limited monarchy to democracy as "a progress toward true respect for the individual" and theorized about further improvements "towards recognizing and organizing the rights of man." Echoing this belief, he went on to write: "There will never be a really free and enlightened State until the State comes to recognize the individual as a higher and independent power, from which all its power and authority are derived, and treats him accordingly."
Although Thoreau believed resistance to unjustly exercised authority could be both violent (exemplified in his support for John Brown) and nonviolent (his own example of tax resistance displayed in Resistance to Civil Government), he regarded pacifist nonresistance as temptation to passivity, writing: "Let not our Peace be proclaimed by the rust on our swords, or our inability to draw them from their scabbards; but let her at least have so much work on her hands as to keep those swords bright and sharp." Furthermore, in a formal lyceum debate in 1841, he debated the subject "Is it ever proper to offer forcible resistance?", arguing the affirmative.
Likewise, his condemnation of the Mexican–American War did not stem from pacifism, but rather because he considered Mexico "unjustly overrun and conquered by a foreign army" as a means to expand the slave territory.
Thoreau was ambivalent towards industrialization and capitalism. On one hand he regarded commerce as "unexpectedly confident and serene, adventurous, and unwearied"and expressed admiration for its associated cosmopolitanism, writing:
I am refreshed and expanded when the freight train rattles past me, and I smell the stores which go dispensing their odors all the way from Long Wharf to Lake Champlain, reminding me of foreign parts, of coral reefs, and Indian oceans, and tropical climes, and the extent of the globe. I feel more like a citizen of the world at the sight of the palm-leaf which will cover so many flaxen New England heads the next summer.
On the other hand, he wrote disparagingly of the factory system:
I cannot believe that our factory system is the best mode by which men may get clothing. The condition of the operatives is becoming every day more like that of the English; and it cannot be wondered at, since, as far as I have heard or observed, the principal object is, not that mankind may be well and honestly clad, but, unquestionably, that corporations may be enriched.
Thoreau also favored bioregionalism, the protection of animals and wild areas, free trade, and taxation for schools and highways. He disapproved of the subjugation of Native Americans, slavery, technological utopianism, consumerism, philistinism, mass entertainment, and frivolous applications of technology.
Thoreau was influenced by Indian spiritual thought. In Walden, there are many overt references to the sacred texts of India. For example, in the first chapter ("Economy"), he writes: "How much more admirable the Bhagvat-Geeta than all the ruins of the East!" American Philosophy: An Encyclopedia classes him as one of several figures who "took a more pantheist or pandeist approach by rejecting views of God as separate from the world", also a characteristic of Hinduism.
Furthermore, in "The Pond in Winter", he equates Walden Pond with the sacred Ganges river, writing:
In the morning I bathe my intellect in the stupendous and cosmogonal philosophy of the Bhagvat Geeta since whose composition years of the gods have elapsed, and in comparison with which our modern world and its literature seem puny and trivial; and I doubt if that philosophy is not to be referred to a previous state of existence, so remote is its sublimity from our conceptions. I lay down the book and go to my well for water, and lo! there I meet the servant of the Brahmin, priest of Brahma and Vishnu and Indra, who still sits in his temple on the Ganges reading the Vedas, or dwells at the root of a tree with his crust and water jug. I meet his servant come to draw water for his master, and our buckets as it were grate together in the same well. The pure Walden water is mingled with the sacred water of the Ganges.
Thoreau was aware his Ganges imagery could have been factual. He wrote about ice harvesting at Walden Pond. And he knew that New England's ice merchants were shipping ice to foreign ports, including Calcutta.
Additionally, Thoreau followed various Hindu customs, including following a diet of rice ("It was fit that I should live on rice, mainly, who loved so well the philosophy of India."), flute playing (reminiscent of the favorite musical pastime of Krishna), and yoga.
In an 1849 letter to his friend H.G.O. Blake, he wrote about yoga and its meaning to him:
Free in this world as the birds in the air, disengaged from every kind of chains, those who practice yoga gather in Brahma the certain fruits of their works. Depend upon it that, rude and careless as I am, I would fain practice the yoga faithfully. The yogi, absorbed in contemplation, contributes in his degree to creation; he breathes a divine perfume, he hears wonderful things. Divine forms traverse him without tearing him, and united to the nature which is proper to him, he goes, he acts as animating original matter. To some extent, and at rare intervals, even I am a yogi.
Thoreau read contemporary works in the new science of biology, including the works of Alexander von Humboldt, Charles Darwin, and Asa Gray (Charles Darwin's staunchest American ally). Thoreau was deeply influenced by Humboldt, especially his work Kosmos.
In 1859, Thoreau purchased and read Darwin's On the Origin of Species. Unlike many natural historians at the time, including Louis Agassiz who publicly opposed Darwinism in favor of a static view of nature, Thoreau was immediately enthusiastic about the theory of evolution by natural selection and endorsed it, stating:
The development theory implies a greater vital force in Nature, because it is more flexible and accommodating, and equivalent to a sort of constant new creation. (A quote from On the Origin of Species follows this sentence.)
Thoreau's careful observations and devastating conclusions have rippled into time, becoming stronger as the weaknesses Thoreau noted have become more pronounced [...] Events that seem to be completely unrelated to his stay at Walden Pond have been influenced by it, including the national park system, the British labor movement, the creation of India, the civil rights movement, the hippie revolution, the environmental movement, and the wilderness movement. Today, Thoreau's words are quoted with feeling by liberals, socialists, anarchists, libertarians, and conservatives alike.— Ken Kifer, Analysis and Notes on Walden: Henry Thoreau's Text with Adjacent Thoreauvian Commentary
Thoreau's political writings had little impact during his lifetime, as "his contemporaries did not see him as a theorist or as a radical, viewing him instead as a naturalist. They either dismissed or ignored his political essays, including Civil Disobedience. The only two complete books (as opposed to essays) published in his lifetime, Walden and A Week on the Concord and Merrimack Rivers (1849), both dealt with nature, in which he loved to wander." His obituary was lumped in with others rather than as a separate article in an 1862 yearbook.Nevertheless, Thoreau's writings went on to influence many public figures. Political leaders and reformers like Mohandas Gandhi, U.S. President John F. Kennedy, American civil rights activist Martin Luther King, Jr., U.S. Supreme Court Justice William O. Douglas, and Russian author Leo Tolstoy all spoke of being strongly affected by Thoreau's work, particularly Civil Disobedience, as did "right-wing theorist Frank Chodorov [who] devoted an entire issue of his monthly, Analysis, to an appreciation of Thoreau."
Thoreau also influenced many artists and authors including Edward Abbey, Willa Cather, Marcel Proust, William Butler Yeats, Sinclair Lewis, Ernest Hemingway, Upton Sinclair, E. B. White, Lewis Mumford, Frank Lloyd Wright, Alexander Posey, and Gustav Stickley. Thoreau also influenced naturalists like John Burroughs, John Muir, E. O. Wilson, Edwin Way Teale, Joseph Wood Krutch, B. F. Skinner, David Brower, and Loren Eiseley, whom Publishers Weekly called "the modern Thoreau". English writer Henry Stephens Salt wrote a biography of Thoreau in 1890, which popularized Thoreau's ideas in Britain: George Bernard Shaw, Edward Carpenter, and Robert Blatchford were among those who became Thoreau enthusiasts as a result of Salt's advocacy. Mohandas Gandhi first read Walden in 1906 while working as a civil rights activist in Johannesburg, South Africa. He first read Civil Disobedience "while he sat in a South African prison for the crime of nonviolently protesting discrimination against the Indian population in the Transvaal. The essay galvanized Gandhi, who wrote and published a synopsis of Thoreau's argument, calling its 'incisive logic [...] unanswerable' and referring to Thoreau as 'one of the greatest and most moral men America has produced'." He told American reporter Webb Miller, "[Thoreau's] ideas influenced me greatly. I adopted some of them and recommended the study of Thoreau to all of my friends who were helping me in the cause of Indian Independence. Why I actually took the name of my movement from Thoreau's essay 'On the Duty of Civil Disobedience', written about 80 years ago."
Martin Luther King, Jr. noted in his autobiography that his first encounter with the idea of nonviolent resistance was reading "On Civil Disobedience" in 1944 while attending Morehouse College. He wrote in his autobiography that it was, "Here, in this courageous New Englander's refusal to pay his taxes and his choice of jail rather than support a war that would spread slavery's territory into Mexico, I made my first contact with the theory of nonviolent resistance. Fascinated by the idea of refusing to cooperate with an evil system, I was so deeply moved that I reread the work several times. I became convinced that noncooperation with evil is as much a moral obligation as is cooperation with good. No other person has been more eloquent and passionate in getting this idea across than Henry David Thoreau. As a result of his writings and personal witness, we are the heirs of a legacy of creative protest. The teachings of Thoreau came alive in our civil rights movement; indeed, they are more alive than ever before. Whether expressed in a sit-in at lunch counters, a freedom ride into Mississippi, a peaceful protest in Albany, Georgia, a bus boycott in Montgomery, Alabama, these are outgrowths of Thoreau's insistence that evil must be resisted and that no moral man can patiently adjust to injustice."
American psychologist B. F. Skinner wrote that he carried a copy of Thoreau's Walden with him in his youth. and, in 1945, wrote Walden Two, a fictional utopia about 1,000 members of a community living together inspired by the life of Thoreau. Thoreau and his fellow Transcendentalists from Concord were a major inspiration of the composer Charles Ives. The 4th movement of the Concord Sonata for piano (with a part for flute, Thoreau's instrument) is a character picture and he also set Thoreau's words.
In the early 1960s Allan Sherman referred to Thoreau in his song parody "Here's To Crabgrass" about the suburban housing boom of that era with the line "Come let us go there and live like Thoreau there."
Actor Ron Thompson did a dramatic portrayal of Henry David Thoreau on the 1976 NBC television series The Rebels.
Thoreau's ideas have impacted and resonated with various strains in the anarchist movement, with Emma Goldman referring to him as "the greatest American anarchist".Green anarchism and anarcho-primitivism in particular have both derived inspiration and ecological points-of-view from the writings of Thoreau. John Zerzan included Thoreau's text "Excursions" (1863) in his edited compilation of works in the anarcho-primitivist tradition titled Against civilization: Readings and reflections. Additionally, Murray Rothbard, the founder of anarcho-capitalism, has opined that Thoreau was one of the "great intellectual heroes" of his movement. Thoreau was also an important influence on late-19th-century anarchist naturism. Globally, Thoreau's concepts also held importance within individualist anarchist circles in Spain, France, and Portugal.