A native curiosity in the human spirit loves to explore the “what if” questions that test the boundaries of existence as we know it. What if certain humans possessed certain superhuman powers? What if humanity colonized other planets and interacted politically with other civilized species? What if good and evil battled for control of an intra-galactic empire?

These “what-if” questions form the basis of the genre of books, movies, TV shows, and even comics known as sci-fi. The genre explores these questions by placing them in their own worlds, a world necessarily ordered differently from ours, and seeing how they work.

This otherworldly exploration is the essence of science fiction, but it also is a ground for caution — at least for nerds like yours truly who are also Christians. As much as science fiction worlds can be stimulating, entertaining, fascinating, and any other contemplative participle one wishes to apply, they are also fundamentally different from the creation of the one true God. God the Creator designed this world and declared it to be “very good” (Genesis 1:31). Any other world is therefore less Christian.

Please do not misunderstand the point. This is not a general condemnation of all science fiction, nor a warning against asking the “what-if” questions. Such questions are natural to humanity. Sooner or later, these questions will naturally suggest themselves to an inquiring mind with sufficient leisure (especially if primed by an existing abundant stock of sci-fi literature). And, if handled in proper submission to a Christian worldview and the rule of Christ, such questions can lead us to greater praise of God for the one world in which we do live.

At the same time, Christian nerds who love sci-fi universes should be aware that those universes often function within non-Christian worldviews, and they should be aware of the assumptions and moral practices they thereby take on. Almost every sci-fi universe has a worldview.

“Star Trek” (at least the earlier shows) applied modernist humanism. Humanity has been perfected through education and liberal values. Earth has become a beautiful utopia. Virtuous humans sail throughout the galaxy engaging in scientific inquiry and in diplomacy with the other intelligent species postulated by some evolutionary theories.

By contrast, “Doctor Who” (at least the rebooted show) embraces postmodernism. Humanity spreads throughout the stars but only to export corruption and despair from the grieving hulk of their ruined planet. The rules of reality — from the powers of the sonic screwdriver to the continuity of the time continuum — exist only to be rewritten, or even tricked. The universe teeters on the brink of catastrophe and despair, and only the superior intellect and will of one character can save the day.

“Star Wars” features a mystical dualism, where coequal powers of good and evil are locked in a permanent battle for control. By contrast, the Christian God is the one true Lord of all, evil only has power as he allows, and the existence of present conflict does not create a doubt of the final outcome.

The short-running series “Firefly” adopts a libertarian theme in a “Star Wars”-like universe. Setting aside the mystical dualism of “the Force,” which only select gifted individuals could possess, how would ordinary people survive on the fringes of an overbearing — and probably evil — galactic empire? “Firefly” answers: ordinary people survive breaking the law — smuggling, prostitution, whatever is necessary to survive. This flies in the face of the Christian belief that God created authority for good.

The list could go on. While they don’t necessarily fit clearly into the science fiction genre, superhero movies reinvent the pagan pantheon: characters with godlike powers but humanlike motives, emotions, and limitations struggle against each other to devastating effect. Multiverse theories, wherever they arise, postulate a creation based on random chance, not on a personal Creator. “Dune” is less familiar to this author, but it seems to have at least Islamic overtones, if not a full Islamic worldview.

Readers will likely think of “sci-fi” (or perhaps “fantasy” is the better word) series that are unlike this earth and yet do not seem to embrace non-Christian worldviews. What about Narnia, Middle Earth, even Hogwarts? What about a sci-fi show like “The Expanse,” which tries to imagine a realistic future of space colonization?

This author understands from personal experience how passionate nerds can get about defending their favorite sci-fi universes. The point is not to write them off entirely, and objections like the examples named above are well-taken. But notice how these works divide themselves neatly into two types. One type (sometimes called “hard sci-fi”) emphasizes realism, which becomes a limiting principle to keep it from going too far astray from this world.

The other type — often from Christian writers or those influenced by Christianity — applies Christian themes to fantastical subjects. For instance, “The Chronicles of Narnia,” “The Lord of the Rings,” and the “Harry Potter” series all feature a powerful character who lays down his life to save those he loves and later comes back to life. In all three, good and evil are clearly distinguishable, and good ultimately triumphs through a series of unforeseen reversals.

Thus, not every science fiction or fantasy universe embraces a non-Christian worldview. But those consistent with Christianity usually track closely either to the biblical storyline or to the world as we know it.

The reason is that Christians don’t need a science fiction world in which to explore or “live out” the ramifications of our worldview. Our “science fiction” world is the real one. We believe in the God who created all things, who ordered human relationships between husband and wife, between parents and children, between individuals and communities and churches and governments. Adherents of other worldviews create fictional worlds, where their ideas actually work, as an escape from a world that does not meet their expectations. Christians don’t need to create another world because the one who designed this one has already given us a perfect guide by which to live.

Thus, the Christian worldview becomes the end of all “what-if” questions. Pursuing intellectual curiosity is fine, but that pursuit must eventually end — ideally by obtaining its aim. As G.K. Chesterton wrote, “the object of opening the mind, as of opening the mouth, is to shut it again on something solid.” Having opened the mind to various possibilities of science fiction, let the Christian conclude by returning to the real world. Let the Christian conclude that God’s world is best, and God’s way is best. If anything had been better a different way, God would have made it that way. After investigating every possibility, let the Christian kneel before the Savior in open-mouthed admiration, confessing with greater understanding than before, “He has done all things well” (Mark 7:37).