I recently read The Universe Next Door, by James Sire, save the last two chapters. It was a good, actually entertaining read, if one doesn't mind dragging a little. It included lots of interesting illustrations, historical stories and writings, and mind-boggling philosophy on a grand scale.
What Mr. Sire set out to write was a worldview catalog, analyzing in chronological order most of the major worldviews from about 1500 onwards. The chapters went in this order:
Theism -> Deism -> Naturalism -> Nihilism -> Existentialism -> Eastern Monastic Pantheism -> New Age -> Postmodernism.
Let me try to give an incredibly brief explanation for why each of these worldviews followed upon the heels of its predecessor.
Thesim requires a relationship with One Creator God. Seperation from this God means that we cannot know Him unless He reveals Himself to us. So, when He did not do so, Deism arrived.
Deism assumes the One Creator God, and historically holds the same values as Theism, but claims that God has backed out of the universe, and either no longer cares, or cannot be known by special revelation, only by what He made. This begs the question, how do we know God was there in the beginning? So we move to naturalism.
Naturalism desposes with God, claiming that matter is the end-all and be-all. Values still exist, for some reason, but now we need not feel guilty about breaking the rules, after all, there is no God to hold us accountable. This leads to Nihilism.
Nihilism assumes that the entire idea of value is preposterous. Being entirely material, we cannot even know that we are. The chances that we are percieving reality with our senses are slim. We may not even really exist, nor may anyone else, and if we do, we are but a pillar of salt, a tower of matter with specific reactions. Nothing matters. Life cannot have meaning. No worldview can be correct. Nihilism leads to suicide, which, as a matter of practicality, has never been a predominant worldview.
Here is an interesting branch in the road. Nihilism leads to suicide, so how did we get to existentialism? By not thinking. Nihilism is arrived at by two facts being true: 1) the Nihilist does not have a right relationship with God. 2) the Nihilist thinks carefully and logically.
The Nihilist cannot change 1), but would very much not like to commit suicide, so changes 2), and assumes Existentialism, in which matter and thought are two entirely seperate fields, the objective and the subjective. The objective world may be entirely explainable a la Naturalism, but the subjective world is still there. So, one may seclude thoughts of God, value, good, and evil to the subjective mind, and strongly hold in the objective world that God is scientifically impossible, good and evil nonexistant, and value pointless. This defies reason.
Once reason is defied, Existentialism can be improved upon by Eastern Pantheistic Monism. All is one, matter is not reality, the point in life is to become part of the one. "This too is vanity."
New Age and Postmodernism fare no better
The whole point of this abstract, overly generalized, error-riddled progression is to point out an illustration.
Faith in God, knowing God, is at the apex of the illustration. Falling from that the thinking person falls through Deism and Naturalism and, finding no rest, lands in Nihilism, which, truly believed, becomes suicidism. Most people don't want to die, and so cease to be thinking people and fall even farther, if that is possible, into mindless existentialism, etc.
What people need is a right relationship with God. We must realize that the Truth, when it is shown to man, leads to despair in the absence of the Truth-giver. If we know how things really are, and Christ is not present in our hearts, we become nihilists. If Christ is present, we become Theists.
Anyways, I thought that was an interesting way of looking at it.