A nation is a efined cultural and social community. In as much as most members never meet each other, yet feel a common bond, it may be considered an imagined community. One of the most influential doctrines in Western Europe and the Western hemisphere since the late eighteenth century is that all humans are divided into groups called nations. Nationhood is an ethical and philosophical doctrine and is the starting point for the ideology of nationalism; a nation is a form of self-defined cultural and social community. Members of a "nation" share a common identity, and usually a common origin, in the sense of history, ancestry, parentage or descent. A nation extends across generations, and includes the dead as full members. Past events are framed in this context: for example, by referring to "our soldiers" in conflicts which took place hundreds of years ago. More vaguely, nations are assumed to include future generations.