natural gas Colourless, highly flammable gaseous hydrocarbon con¬ sisting primarily of methane and ethane. It may also contain heavier hydrocarbons, carbon dioxide, hydrogen, hydrogen sulfide, nitrogen, helium, and argon. It commonly occurs in association with crude oil (see petroleum). Natural gas is extracted from wells drilled into the Earth. Some natural gas can be used as it comes from the well, without any refining, but most requires processing. It is transported either in its natural gaseous state by pipeline or, after liquefaction by cooling, by tankers. Liquefied natural gas occupies only about 1/600 of the volume of the gas. It has grown steadily as a source of energy since the 1930s.
natural law In jurisprudence and political philosophy, a system of right or justice common to all humankind and derived from nature rather than from the rules of society, or positive law. The concept can be traced to Aristotle, who held that what was “just by nature” was not always the same as what was “just by law.” In one form or another, the existence of natural law was asserted by the Stoics (see Stoicism), Cicero, the Roman jurists, St. Paul, St. Augustine, Gratian, St. Thomas Aquinas, John Duns Scotus, William of Ockham, and Francisco SuArez. In the modern period, Hugo Grotius insisted on the validity of natural law even on the assump¬ tion that God does not exist, and Thomas Hobbes defined a law of nature as “a precept of general rule found out by reason, by which a man is for¬ bidden to do that which is destructive of his life.” Hobbes attempted to construct an edifice of law by rational deduction from a hypothetical “state of nature” and a social contract of consent between rulers and subjects. John Locke departed from Hobbes in describing the state of nature as an early society in which free and equal men observe the natural law. Jean- Jacques Rousseau postulated a savage who was virtuous in isolation and actuated by two principles “prior to reason”: self-preservation and com¬ passion. The authors of the U.S. Declaration of Independence refer only briefly to “the Laws of Nature” before citing equality and other “unalien¬ able” rights as “self-evident.” The French Declaration of the Rights of AAan and of the Citizen asserts liberty, property, security, and resistance to oppression as “imprescriptible natural rights.” Interest in the concept of natural law declined dramatically in the 19th century, partly as a result of skeptical attacks by Jeremy Bentham and other proponents of utilitarian¬ ism; it was revived in the mid-20th century in light of the crimes commit¬ ted by the Nazi regime during World War II. Skepticism of natural law and natural rights remained strong, however, and later writers almost invariably talked of human rights rather than natural rights.
natural selection Process that results in adaptation of an organism to its environment by means of selectively reproducing changes in its geno¬ type. Variations that increase an organism’s chances of survival and pro¬ creation are preserved and multiplied from generation to generation at the expense of less advantageous variations. As proposed by Charles Darwin, natural selection is the mechanism by which evolution occurs. It may arise from differences in survival, fertility, rate of development, mating suc¬ cess, or any other aspect of the life cycle. Mutation, gene flow, and genetic drift, all of which are random processes, also alter gene abundance. Natu¬ ral selection moderates the effects of these processes because it multiplies
the incidence of beneficial mutations over generations and eliminates harmful ones, since the organisms that carry them leave few or no descen¬ dants. See also selection.
naturalism Aesthetic movement of the late 19th to early 20th century. The movement was inspired by the principles and methods of natural sci¬ ence, especially Darwinism, which were adapted to literature and art. In literature, naturalism extended the tradition of realism, aiming at an even more faithful, pseudoscientific representation of reality, presented with¬ out moral judgment. Characters in naturalistic literature typically illus¬ trate the deterministic role of heredity and environment on human life. The movement originated in France, where its leading exponent was Emile Zola. In America it is associated with the work of writers such as Stephen Crane and Theodore Dreiser. Visual artists associated with naturalism chose themes from life, capturing subjects unposed and not idealized, thus giv¬ ing their works an unstudied air. Following the lead of the Realist painter Gustave Courbet, painters chose themes from contemporary life, and many deserted the studio for the open air, finding subjects among peasants and tradespeople, capturing them as they found them. As a result, finished canvases had the freshness and immediacy of sketches. Zola, the spokes¬ man for literary naturalism, was also the first to champion Edouard Manet and the Impressionists (see Impressionism). While naturalism was short¬ lived as a historical movement, it contributed to art an enrichment of real¬ ism, new areas of subject matter, and a largeness and formlessness that was closer to life than to art. Its multiplicity of impressions conveyed the sense of a world in constant flux.
naturalism In philosophy, the theory that affirms that all beings and events in the universe are natural and therefore can be fully known by the methods of scientific investigation. Though naturalism has often been equated with materialism, it is much broader in scope. Strictly speaking, naturalism has no ontological bias toward any particular set of categories of reality: dualism and monism, atheism and theism, idealism and materialism are all compatible with it. Naturalism was most influential in the 1930s and ’40s, chiefly in the U.S. among philosophers such as F.J.E. Wood- bridge (1867-1940), Morris R. Cohen (1880-1947), John Dewey, Ernest Nagel (1901-85), Sidney Hook (1902-89), and W.V.O. Quine.
naturalistic fallacy Fallacy of treating the term “good” (or any equivalent term) as if it were the name of a natural property. In 1903 G.E. Moore presented in Principia Ethica his “open-question argument” against what he called the naturalistic fallacy, with the aim of proving that “good” is the name of a simple, unanalyzable quality, incapable of being defined in terms of some natural quality of the world, whether it be “plea¬ surable” (John Stuart Mill) or “highly evolved” (Herbert Spencer). Since Moore’s argument applied to any attempt to define good in terms of something else, including something supernatural such as “what God wills,” the term “naturalistic fallacy” is not apt. The open-question argu¬ ment turns any proposed definition of good into a question (e.g., “Good means pleasurable” becomes “Is everything pleasurable good?”)— Moore’s point being that the proposed definition cannot be correct, because if it were the question would be meaningless.
naturalization Process of granting nationality or citizenship to an alien. It may be granted after voluntary application or through legislation, marriage to a citizen, or parental action. Involuntary naturalization occurs when one’s home territory is annexed by a foreign state. Qualifications for natu¬ ralization may include a minimum residency period, a minimum age, law- abiding character, good health, self-sufficiency, satisfactory knowledge of the new country, and willingness to give up one’s former nationality.
Nature Conservancy Nonprofit organization dedicated to environ¬ mental conservation and the preservation of biodiversity, founded in 1951, that operates the largest private system of nature sanctuaries in the world. It owns and manages more than 1,500 preserves throughout the U.S., comprising more than 9 million acres (3.8 million hectares) of ecologi¬ cally significant land, and has expanded into Latin America and the Pacific. Government-administered programs identify the relative abun¬ dance of plant and animal species and the habitats they need to survive, and the Conservancy then acquires—through gifts, exchanges, easements, debt-for-nature swaps, purchases, and other nonconfrontational arrangements—areas that are home to threatened species.