One of the tests of any worldview is whether one can live within it consistently. On this test the worldview called naturalism - i.e. the view that the natural world is all there is, no supernatural entities exist - falls short since many, if not most, naturalists find that they have to give up some beliefs and assumptions that are very difficult to let go. Among the things for which there is no room in a logically consistent naturalistic ontology are the following:
1. ultimate meaning in life
2. free will
3. objective moral right and wrong
4. the intrinsic value of human beings
5. objective human rights
6. mind/consciousness
7. an adequate ground for beauty, love and truth
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, though, compels one to regard them all as illusions, but few naturalists can live consistently with that. They find themselves constantly acting as if their lives have meaning, as if there really are objective moral rights and wrongs, as if they have free will.
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, human rights, free will and the rest from the storehouse of 2000 years of Christian heritage, because their own worldview cannot provide them.
But when one has to poach from competing visions of reality in order to make life bearable one is tacitly sacrificing any claim to be holding a rational, coherent worldview. To be consistent a naturalist should indeed be a nihilist and accept the emptiness, sterility and despair nihilism entails, yet even though some naturalists recognize these bitter fruits of their view of things, few can bring themselves to accept them. They embrace the naturalism while simply suppressing or ignoring the logical implications as if they don't matter.
For those who do accept the consequences of their naturalism, the loss of the aforementioned crucial existential human needs is more than compensated for, in their minds, by the liberation from God that lies at the heart of naturalism. It's all worth it, they tacitly calculate, to be free of any obligation to a supreme being.
Naturalists are free to embrace this schizoid view of life, of course, but they're not free to live as if they can hold on to those existential needs while denying the only adequate ground for them and at the same time declare their worldview to be more rational than the Judeo-Christian alternative.
