A Higher Purpose addresses the general question of meaninglessness, to be sure, with or without immortality. The problem is that most of our lives are taken up with personal concerns. A Higher Purpose involves the sublimation of individuality. Does that part of our lives devoted to a Cause only have meaning, and is the rest marking time? Is the War the only thing that matters, not the fate of the individual soldier?
If the fate of the individual matters, then eternal life matters. I, personally, have no more than a sense of the likelihood of it, and therefore cannot be entirely free from disquietude. There may be those with conviction sufficient to free them. On the other hand, confidence, even if imperfect, is better than a sense of "riding your own melt".
If I read correctly correctly what you are asking, I would say that it is called religious existentialism, originating in the writings of Kierkegaard. Kierkegaard began by attacking Hegelianism, which threatened to become the theology of his day, and interpreted the meaning of everything in terms of Higher Purpose. To Kierkegaard, the System was a beautiful construction, but deficient, because it leaves out the most important question for the individual, which is that of his individual destiny. This very omission undermines the System itself: how can we be concerned with the fate of humanity (the Higher Purpose) and not care about the fate of the individual? |