A philosophy that became influential in the 19th century. Transcendentalism rejects the idea that knowledge can be fully derived from experience and observation of the physical world; rather, an individual should examine the way she comes to know things—in other words, the thought process itself—and focus on her connection to the divine, which exists beyond the senses, but which can be known through intuition and feeling. American transcendentalism reached its peak in New England in the 1840s, under the leadership of Ralph Waldo Emerson. Emerson argued that, while the physical world is important, providing us with necessary goods and frequent beauty, people should live their lives based on truths grasped through reason, not just physical perception. People will find truth within themselves; therefore, self-reliance and individuality are critical. Emerson served as a mentor to Thoreau, who became another leading American transcendentalist.

Mexican-American War (1846-1848)

The Mexican-American War was fought over boundary disputes between the two countries that were heightened by the 1845 United States annexation of Texas, which had won its independence from Mexico in 1836, but which Mexico still considered part of its territory. Another factor leading to the war was the belief by many Americans that it was the nation’s "Manifest Destiny" to expand their territory into lands legally owned by Mexico. During the war, U.S. forces invaded Mexico and occupied its capital, Mexico City. In the subsequent Treaty of Guadalupe Hidalgo, Mexico officially recognized U.S. sovereignty over Texas and ceded land that would later constitute the states of California, Nevada, Utah, most of Arizona and New Mexico, and parts of Colorado and Wyoming. Thoreau and other opponents of the war argued that the campaign constituted an unnecessary act of aggression and that it was pursued based on arrogance rather than any philosophically justifiable reasons.

The Abolitionist Movement

Drive in New England and other Northern states that worked toward the abolishment of slavery in the United States. Once considered a fringe movement, the abolitionist cause grew in supporters and in strength throughout the 19th century, although most American (even in the Northern states) opposed the idea of armed conflict to end slavery even as the Civil War began as a result of the succession of Southern states in 1861. Thoreau wrote about indefensibleness of slavery and took on an active role in the growing abolitionist movement. He assisted fugitive slaves on the Underground Railroad, and later took an unpopular stand by announcing his support for John Brown, who in 1859 had sought to incite a slave rebellion by seizing a federal arsenal in Harper’s Ferry, Virginia, and was then executed.

Poll Taxes

Taxes that levied against all adults regardless of income to support local and state governments in many states until they were outlawed by the ratification of the 24th Amendment to the U.S. Constitution in 1964. Thoreau’s refusal to pay his poll tax in Concord, Massachusetts, in 1854 as a protest against slavery and the Mexican-American War led to his arrest and overnight incarceration.

Popular pages: Civil Disobedience