A worldview is the set of assumptions we hold, consciously or unconsciously, that help us interpret our experience of the world. One of the tests of any worldview is whether one can live consistently with the consequences entailed by it.
On this test the worldview called naturalism, i.e. the view that nature is all there is, fails since many, if not most, naturalists find that they have to give up things that are very difficult if not impossible to live without. Among the items for which there is no room in a naturalist ontology are the following:
1. ultimate meaning in life
2. free will
3. objective moral right or wrong
4. intrinsic value of human beings
5. mind/consciousness
6. belief that love is more than just a neurochemical response
7. an adequate ground for objective beauty and truth
8. an adequate ground for human rights
On the other hand, not only do each of these fit comfortably in a classical Christian worldview, it could be argued that they're actually entailed by that view. The logic of naturalism, however, compels one to regard them all as either subjective and arbitrary or complete illusions, but few naturalists can live consistently with that.
They find themselves constantly acting as if their lives do have meaning, as if there really are objective moral rights and wrongs, as if they do have free will, as if their love for their families is more than just chemistry, and as if there really are objective human rights.
They can only deny the reality of these things at the theoretical level, but in the way they live their everyday lives they affirm their reality over and over again. They find themselves forced, in a sense, to become poachers, helping themselves to meaning, morality, free will and the rest from the storehouse of 2000 years of Christian heritage, because there's no room for them in naturalism.
But when one has to pilfer one's deepest convictions and values from competing visions of reality in order to make life bearable one is tacitly sacrificing any claim to holding to a rational, coherent worldview. To be consistent a naturalist should be a nihilist and accept the emptiness that that entails, yet even though some naturalists see that, few bring themselves to accept it.
For those who do, the loss of the aforementioned crucial existential human needs is more than compensated for, in their minds, by the liberation from God that naturalism makes possible, but this is a liberation from the only adequate ground that could sustain those profound human needs.
For many who yearn for liberation from a cosmic Creator, either the consequences don't occur to them, or if they do, they're often ignored as if they don't exist.
Naturalists are free to do this, of course, but they're not free to declare their worldview rational if they do.
