The Infinitive of Go
John Brunner
 For the first significant test using a live person, a diplomatic agent is Posted to a foreign embassy from the USA. The test is an abject failure, with the agent demanding a countersign upon arriving at his destination, and then shooting himself and triggering a destructive failsafe in the package of documents he was carrying. It is assumed that the Posting affected the agent's sanity. Faced with termination of the project, Dr. Justin Williams, the inventor of the technology, arranges to have himself Posted from the same embassy back to his research laboratory. He finds himself in a world which is subtly different from his own. For one thing, Cinnamon Wright, his beautiful but cold African-American collaborator, is suddenly an ardent lover. Eventually she admits to him that, like the Cinnamon Wright from his world, she was Posted, and once worked for him in a world where he hated her, even though she was attracted to him. As the story progresses, they realize that when humans are Posted, their inner desires influence the outcome, tipping them into alternate universes. However, they are not prepared for outcome of the next Posting: A Dr. Eduardo Landini has to be Posted back from an orbiting satellite for emergency surgery following a mechanical accident. But the being who emerges is not a man. He is a humanoid descended from baboons, who claims to be Ed Landini, and tells the doctors attending him that he is guaranteed to be biologically compatible with humans, otherwise he would not be there. He reveals that in his world the Posting technology is well understood. However, only mystics and "Pilgrims" elect to be Posted, because they know they will go to another world. It was only his desperate situation that forced him to take the chance himself. The problem is this: the Poster links two congruent spaces, but it searches many universes to find the best match. When all factors are accounted for, including a person's state of mind and the state of the machine itself, the best match is more likely to be found in a machine from another universe. This is how a Dr. Landini arrived that is a man descended from baboons but speaking English and coming from a world with almost exactly the same history as the one on which he arrived. Although evolution took a different track on his world, the outcome was almost exactly the same as on the world where he arrived; had it been different, he would have gone to a different universe. The person who first comes to understand this is not a scientist, but a philosopher. For intelligent beings, the Poster acts as a sort of "equalizer" between universes, introducing worlds where the technology is new to worlds where it is understood. The world from which Landini came was one in which the technology was being pushed further. Posters were being built in large numbers and launched across huge distances of interplanetary space, since the further the distance in the transfer, the greater the difference between the universes linked by the Poster. However, Landini himself becomes the focus of trouble. Rumors about his appearance inspire revulsion among staff members at the facility, and as those rumors spread into the general population, politicians, pundits, religious leaders and rabble rousers begin exploiting the fears generated. Landini himself has no stomach for the attention, and openly shows his contempt for the behavior of the humans around him. Despite his training and education, he has significant personality problems that isolated him even from his own kind. One of the things he tells Justin and Cinnamon is that a typical outcome from contact via the Posters is that the inventors of the devices go insane. Justin begins to feel he is right. The world is spiraling out of control around him, and he has had to reconcile his initial feelings of triumph over the creation of the device with the knowledge that an infinite number of people in other universes invented it long before him. The final chapter has Myron Chester, the financier of the development effort (who was a ruthless power broker in Justin's original world) revealing a secret. He had suspected that Justin and Cinnamon had both been changed by being Posted because neither had mentioned their secret project-within-a-project: To discover what would happen if a Poster was used without another Poster acting as a destination. Once it became apparent that Posters linked different universes he began sending information rather than objects. Soon he accumulated a collection of books, newspapers and other media from other Earths, some fantastically different from the one he lived on. He is optimistic that once people begin being Posted this way, they will receive the Pilgrims Landini talked about, who go to help other universes. He believes that the Posters will necessarily send people to the universes where they can do the most good, because that is what their state of mind will require. One message he received says that in worlds where the inventors of Posting are among the first to be Posted, the outcome is usually good for those left behind. If this is not done, the outcome is usually very bad. Since both Justin and Cinnamon had been posted, this foretells a likelihood of a positive outcome in this reality.