here are four core debates which permeate the study of nations and nationalism. First among these is the question of how to define the terms "nation" and "nationalism." Second, scholars argue about when nations first appeared. Academics have suggested a variety of time frames, including (but not limited to!) the following:
Nationalists argue that nations are timeless phenomena. When man climbed out of the primordial slime, he immediately set about creating nations.
The next major school of thought is that of the perennialists who argue that nations have been around for a very long time, though they take different shapes at different points in history.
While postmodernists and Marxists also play in the larger debates surrounding this topic, the modernization school is perhaps the most prevalent scholarly argument at the moment. These scholars see nations as entirely modern and constructed.