Alien aliens (macguffins)

This post started out with another subtitle: unknowable. Then -- a dangerous habit, to be sure -- I started to think.

This series of posts began in advocacy for *alien* aliens, as opposed to the human-in-rubber-suit aliens too common in (especially) TV SF. Certainly, you're thinking, aliens so different as to defy human understanding qualify.

Examples first:

The Eschaton series by Charlie Stross (disclosure: I've read only the first book, Singularity Sky). "Eschaton" is the end of everything, the ultimate destiny of the universe. The fictional Eschaton is an AI so advanced no one can comprehend its thinking.

The Buggers/Formics of Ender's Game. Humanity and this insectoid/hive species fight a battle of extinction because humans and aliens cannot communicate. Humans cannot even convince the aliens we are capable of communication.

The creatures of the Beyond, in Vernor Vinge's Zones of Thought novels, most notably A Fire Upon the Deep. The farther one travels from the galactic core, the deeper mentality becomes. Beings of the Beyond may strike us as good or evil, but their capabilities and motivations are unknowable.

On due reflection, I decided unknowable aliens in fiction are nothing new. They're devices to move forward a plot involving beings we can understand: humans. Lots of fiction uses such devices -- items we don't understand but to which the characters must react. The Maltese falcon is one in the movie of the same name. Ditto the metal briefcase in the movie Ronin. Alfred Hitchcock called the device a Macguffin. Once the story gets underway, you forget to wonder what the MacGuffin really is.

So: in Singularity Sky, we deal with the Eschaton's human agents -- them, we understand. In A Fire Upon the Deep, a Beyond being chases some characters into slow-witted parts of the galaxy, where readers encounter (wonderful) aliens we can understand.

Buggers are a more complicated case. Throughout Ender's Game (the first book of a series, in fact two interlocking series) the Buggers are unknowable. In later books the hive queens suddenly have telepathic linkages with selected humans. The *human* story has progressed, and now the storyteller needs to establish a connection with the aliens -- and that required destrangifying (like that word?) the alien.

Might the universe have aliens so different from humans we'll never understand them? I don't see why not. But unknowable aliens in fiction generally aren't really unknowable, they're props. Tools of the authorial trade. MacGuffins.

Tropes.