The Writer's Almanac with Garrison Keillor

Today is Earth Day. It was first observed in 1970, but its roots go back to the 1962 publication of Rachel Carson's (books by this author) landmark book exposing the effects of pesticides and other chemical pollution on the environment. Troubled by the lack of attention pollution was receiving on the national stage, Wisconsin senator Gaylord Nelson began going on speaking tours, trying to educate people and politicians about environmental issues. And while the public was concerned, the politicians didn't pay much attention.

During the late 1960s, Senator Nelson had the idea to harness the energy and methods of the student protests against the Vietnam War to organize a grassroots conservation movement. At a press conference in 1969, he announced plans for a nationwide demonstration, to take place the following spring. It was a gamble that paid off, and the public's response was enthusiastic. Gladwin Hill wrote in The New York Times: "Rising concern about the environmental crisis is sweeping the nation's campuses with an intensity that may be on its way to eclipsing student discontent over the war in Vietnam." Twenty million people nationwide participated in the first Earth Day, on April 22, 1970, and the government finally took notice, forming the Environmental Protection Agency and passing the Clean Air, the Clean Water, and the Endangered Species Acts.

In 1990, on the 20th anniversary, organizer Denis Hayes took Earth Day to the international arena, and coordinated events in 141 countries worldwide, boosting the awareness and practice of recycling. The year 2000 marked the first time the event was coordinated on the Internet, and the message was the need for clean energy to counteract climate change.

According to the Earth Day Network, Earth Day is celebrated by a billion people, making it the world's largest secular holiday.

It's the birthday of Enlightenment philosopher Immanuel Kant (books by this author), born in Königsberg, Prussia, in 1724. His father was a saddle maker. He studied theology, physics, mathematics, and philosophy at university, and worked for a time as a private tutor; he made very little money, but it gave him plenty of time for his own work. He lectured at the University of Königsberg for 15 years, until he was eventually given a tenured position as professor of logic and metaphysics in 1770. Though he enjoyed hearing travel stories, he never ventured more than 50 miles from his hometown, believing that travel was not necessary to solve the problems of philosophy.

In his most influential work, The Critique of Pure Reason (1781), he argued against Empiricism, which held that the mind was a blank slate to be filled with observations of the physical world, and Rationalism, which held that it was possible to experience the world objectively without the interference of the mind; instead, he synthesized the two schools of thought, added that the conscious mind must process and organize our perceptions, and made a distinction between the natural world as we observe it, and the natural world as it really is. He viewed morality as something that arises from human reason, and maintained that an action's morality is determined not by the outcome of the action, but by the motive behind it. He is also famous for his single moral obligation, the "Categorical Imperative": namely, that we should judge our actions by whether or not we would want everyone else to act the same way.

He wrote, "Two things fill the mind with ever-increasing wonder and awe ... the starry heavens above me and the moral law within me."

It's the birthday of the man who once wrote, "Love and scandal are the best sweeteners of tea," novelist and dramatist Henry Fielding (books by this author), born to the gentry in Somerset, England, in 1707. He began his career writing for the stage, but often found himself in hot water because his plays were invariably political satires, which the government didn't take kindly to. In 1737, probably in response to Fielding's plays, Parliament passed the Theatrical Licensing Act, which required plays to be approved by the Lord Chamberlain; Fielding, knowing that none of his plays were likely to gain approval, retired from the stage and became a novelist.

He's best known for The History of Tom Jones, a Foundling (1749), which recounts the adventures of a lusty but good-hearted young man who falls in love with his neighbor's daughter. On its surface a comic romance, Tom Jones also contains a fair measure of social commentary on the English class system.

It's the birthday of legendary jazz bassist, bandleader, and composer Charles Mingus, sometimes known as "The Angry Man of Jazz," born in Nogales, Arizona, in 1922. Raised in the Watts neighborhood of Los Angeles, his earliest musical influences were the gospel choirs he heard in church, and Duke Ellington on the radio. He was classically trained on the double bass, but found his home in jazz, and in the 1940s toured with Louis Armstrong and Lionel Hampton.

He wrote: "Let my children have music! Let them hear live music. Not noise. My children! You do what you want with your own!"

It's the birthday of poet Louise Glück (books by this author), born in New York City in 1943. She grew up on Long Island, and her father, a Hungarian immigrant, helped invent the X-Acto knife. She attended Sarah Lawrence College and Columbia University, and her first book of poems, called Firstborn, was published in 1968. She won the National Book Critics Circle Award for The Triumph of Achilles (1985), the Pulitzer Prize for her collection The Wild Iris (1992), and was named U.S. poet laureate in 2003.

She tends to write poems that operate, as she puts it, "on a vertical axis of transcendence and grief." She has a word of wisdom for young poets: It never gets easier to write. In the Yale Daily News, she said, "The fantasy exists that once certain hurdles have been gotten through, this art turns much simpler, that inspiration never falters, and public opinion is always affirmative, and there's no struggle, there's no torment, there's no sense that the thing you've embarked on is a catastrophe."