Truth has a variety of meanings, primarily being in accord with fact or reality, fidelity to an original or to a standard or ideal and, in common usage, constancy or sincerity in action or character. The opposite of truth is falsehood, which, correspondingly, can also take on a logical, factual or ethical meaning.

Language and words are a means by which humans convey information to one another. As such, "truth" must have a beneficial use to be retained within language. Defining this potency and applicability can be looked upon as "criteria", and the method used to recognize a "truth" is termed a criterion of truth. Since there is no single accepted criterion, they can all be considered "theories".^{[clarification needed]}

In religious context, truth is regarded as an aspect of God since the deity is reputed to have knowledge of all things (omniscience). Thus God may hold the office of divine judgment, by which all people are ultimately judged.

Various theories and views of truth continue to be debated among scholars and philosophers. There are differing claims on such questions as what constitutes truth: what things are truthbearers capable of being true or false; how to define and identify truth; the roles that revealed and acquired knowledge play; and whether truth is subjective or objective, relative or absolute.

War is an organized, armed, and often a prolonged conflict that is carried on between states, nations, or other parties typified by extreme aggression, social disruption, and usually high mortality. War should be understood as an actual, intentional and widespread armed conflict between political communities, and therefore is defined as a form of political violence. The set of techniques used by a group to carry out war is known as warfare. An absence of war (and other violence) is usually called peace.

In 2003, Nobel Laureate Richard E. Smalley identified war as the sixth (of ten) biggest problems facing the society of mankind for the next fifty years. In the 1832 treatise On War, Prussian military general and theoretician Carl von Clausewitz defined war as follows: "War is thus an act of force to compel our enemy to do our will."

While some scholars see warfare as an inescapable and integral aspect of human culture, others argue that it is only inevitable under certain socio-cultural or ecological circumstances. Some scholars argue that the practice of war is not linked to any single type of political organization or society. Rather, as discussed by John Keegan in his History of Warfare, war is a universal phenomenon whose form and scope is defined by the society that wages it. Another argument suggests that since there are human societies in which warfare does not exist, humans may not be naturally disposed for warfare, which emerges under particular circumstances. The ever changing technologies and potentials of war extend along a historical continuum. At the one end lies the endemic warfare of the Paleolithic^{[citation needed]} with its stones and clubs, and the naturally limited loss of life associated with the use of such weapons. Found at the other end of this continuum is nuclear warfare, along with the recently developed possible outcome of its use, namely the potential risk of the complete extinction of the human species.

Abraham Lincoln ⁱ/ˈeɪbrəhæm ˈlɪŋkən/ (February 12, 1809 – April 15, 1865) was the 16th President of the United States, serving from March 1861 until his assassination in April 1865. He successfully led his country through its greatest constitutional, military and moral crisis – the American Civil War – preserving the Union while ending slavery, and promoting economic and financial modernization. Reared in a poor family on the western frontier, Lincoln was mostly self-educated. He became a country lawyer, a Whig Party leader, Illinois state legislator in the 1830s, and a one-term member of the United States House of Representatives in the 1840s. After a series of debates in 1858 that gave national visibility to his opposition to the expansion of slavery, Lincoln lost a Senate race to his arch-rival Stephen A. Douglas. Lincoln, a moderate from a swing state, secured the Republican Party nomination. With almost no support in the South he swept the North and was elected president in 1860. His election was the signal for seven southern slave states to declare their secession from the Union and form the Confederate States of America. The departure of the Southerners gave Lincoln's party firm control of Congress, but no formula for compromise or reconciliation was found. And the war came.