I think that is an interesting place to go to see what the message of a particular work of science-fiction presents to us. It gives us an image of ourselves, which, while distorted, can cast light on our behavior in helpful ways. I'll start with a villain. The Cybermen!
Oh boy, am I glad those costumes got better. Anyway, never trust a robot, but almost worse, a cyborg. The cybermen present us with a long-standing and prevalent fear of the effects of technology on human beings individually and socially. What happens when technology progresses unchecked? What do we do when our devices seem to have overtaken and control us? From the cybermen and the Borg, to Terminators and Thinking Machines (20 points if you get that last reference), this fear is deep-seated and has lined many a science-fictions author's pockets.
We see this powerfully with the return of the cybermen in the second series of the reboot, episode 5, "Rise of the Cybermen." I guess they weren't worried about giving the ending away on this one, which is good because the message is pretty heavy-handed anyway. First off, the Doctor, Rose, and Mickey find themselves in a parallel universe unexpectedly, but sadly there are no counterparts sporting goatees (20 more points for this one). Rose is most surprised to see a billboard with her long-deceased father, working for Cybus Industries in this universe (subtle with the name there).
But that's not all. In a Bradbury-esque turn, everyone in this universe's London is sporting EarPod devices that pipe that feed information directly into people's brains. This produces a population that is distracted by what they are listening to, browsing, or the phone conversations they are having. Utterlyabsorbed in these activities, no one ever seems to take the EarBuds, er, Pods off. That is a real shame, because these are exactly what the Cybermen will use to control their minds and bring them in for "Upgrades." You see, the head of Cybus industries is trying to "better" humanity by putting the human brain into a metal body, thus freeing us from all the pesky limitations of this squishy bag of meat we walk around in.
There is a lot to consider here. What limits are there to technological progress, for one? The general populace have dumbly accepted the newest gadgets they are given, without considering whether said gadgets are actually helpful or not. Meanwhile, the people at the technological forefront are pushing the boundaries of science with their research. Sounds great, right? That is, unless I like my squishy meatbag. "Progress" is a term that seems to always have positive overtones, and so we can easily be convinced of the moral goodness of a thing simply by tacking this on as an adjective. But technology changes us, and whether it is for better or worse depends often enough on how we use that technology. Is all technological advancement good, or bad? No. But some are more dangerous than others.
Consider the effects of the EarPods. First they absorb a person in such a way that keeps them constantly occupied, constantly distracted. If one spends all of their time absorbed in superficial distractions, we should ask where creative, original, and critical thinking will come from? The brain is as much a tool as a phone, and if we use it poorly on a regular basis, it will degrade and stultify.
Socially, the effects are more obvious. The turn to the internal world is much easier, much more tempting when technology aids it. Meanwhile, real human interaction suffers. People begin to act alike, but the person they all become is superficial, self-absorbed, and frankly boring. But who cares, because cat pictures! It is interesting that the effects are not only the loss of individualism, but of community as well. These are connected. Only a real, substantial, distinct individualism can create a real, substantial, distinct community. A community is a collection of individuals, but because dull and lifeless when all those people are alike in their dull, carbon-copy selves. The heavy-handed metaphor in the episode could only be missed if you were blind and deaf, and therefore unaware that the episode was playing: technology can be a barrier to real human interactions and individuality. Eventually, the people all become so alike they are indistinguishable, becoming Cybermen with no sense of self at all, only that of creating more Cybermen.
Therein lies the final metaphor I want to mention. The Cybermen don't seem to have aspirations to power for power's sake, or some great malevolent desire to simply destroy. Rather, they mindlessly desire to simply create more of themselves, more carbon copies, more people that fit a uniform mold. Order is achieved only through the assimilation of all that makes us unique into a nice, tidy, clean form. Individuality is frightening, because it is unpredictable, and understanding one another is difficult. So when we encounter that which is different, disturbing, or that simply doesn't fit our expectations, we grow unsettled, and often try to fit that difference into our categories. The real danger of consuming technology mindlessly is certainly here, but the warning against enforcing conformity is just as poignant. It's one thing to pat yourself on the back and say "good job for being you, you're not a victim of the conformists!" It's another to look at yourself and ask, "am I the Cyberman? Am I the one who expects conformity?" Prejudice and conformity hold hands most often, and we Christians most of all must be wary of this, because Christ embraces all cultures, all colors, all faces, and does not hold any one cultural mold, any one of them, in higher regard than another.
So the Cybermen are great "aliens," because they hold a mirror up for us. Do I mindlessly consume? What do I do that both dulls my individuality, and separates me from others? Is it important to actually critique and question the technology I use, and how I use it?
These are my musings, and some nuance needs added. Surely all conformity is not bad, right? Well, what do you think?