Here's everything you need to know about the world of Foundation, created by Isaac Asimov and brought to life in the Apple TV+ series by showrunner David Goyer. In 1942, legendary science-fiction writer Isaac Asimov introduced readers to a fascinating and complex future timeline, one inspired by real-world history - specifically by the collapse of the Roman Empire. In Asimov's story, humanity had expanded across the stars and established an empire that ruled the entire galaxy; but, like the Roman Empire before it, it was doomed to collapse.

This was predicted by mathematician Hari Seldon, who had mastered the science of psychohistory that allowed him to foretell the great movements of society. "The Empire will vanish and all its good with it," Seldon insisted. "Its accumulated knowledge will decay and the order it has imposed will vanish. Interstellar wars will be endless; interstellar trade will decay; population will decline; worlds will lose touch with the main body of the Galaxy - and so matters will remain." According to Seldon, the coming galactic Dark Ages would last for 30,000 years - but he believed certain actions could be taken to reduce that period of chaos and uncertainty to a single millennium. Asimov's Foundation series told the tale of the people who fought to save civilization, in accordance with Seldon's predictions.

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The concept is a grand one, and it seems perfectly fitting that Foundation has been brought to life in 2021, a time when nobody quite knows what to expect from the future - and modeling suggests catastrophes lie ahead. Still, Foundation's fundamental message remains one of hope, for Asimov's writings assure us that the darkness can be driven back. Here's all you need to know about the world of Foundation.

Foundation's Empire & Three Emperors Explained

Foundation Emperors on Thrones

Foundation opens in a time of peace and stability. The Empire rules the galaxy with an iron fist, holding a monopoly on advanced technology and military might. This is best represented by the Jump Drives that allow Imperial ships to travel through space almost instantly by accessing a higher plane of reality, technology that has not been shared with the general public or individual worlds and that allows the Empire to respond to threats with a speed that terrifies any potential opponents. The Empire is seen as the culmination of human history, the pinnacle of human achievement, and knowledge of humanity's humble beginnings on Earth has been forgotten. All power and might in the galaxy is now centered on Trantor, where the Emperor rules.

The Emperors are only a background presence in Asimov's books and short-stories, but David Goyer has reinvented them to give the Empire a face. In Apple TV+'s Foundation series, the Emperors maintain a "genetic dynasty," with the rule of one man - Cleon - maintained through cloning. Each Emperor believes his authority is absolute, derived from his being the continuation of Cleon's will, and at any one time there are three figures standing side-by-side at the head of the Empire; Brother Dawn, the youngest clone who is being trained for the throne, Brother Day who sits upon it currently, and Brother Dusk, who has become too old to continue and has passed the throne on. Of course, for all the Emperors may insist on continuity, in reality each grows up in the shadow of their predecessor's rule, so there are differences in approach and rule. Still, the never-changing face of the Emperor serves as a powerful symbol of the Empire's nature, of its resistance to change. It's as Eto Demerzel says to Brother Dawn about him - the Emperors - always choosing the same option (violence) when presented with an issue.

Trantor, The Galactic Capital in Foundation

Foundation Trantor

The galactic capital in Foundation is Trantor, a city-planet - or ecumenopolis - that has been entirely urbanized. As Asimov describes it:

"All the land surface of Trantor, 75,000,000 square miles in extent, was a single city. The population, at its height, was well in excess of forty billions. This enormous population was devoted almost entirely to the administrative necessities of Empire, and found themselves all too few for the complications of the task. (It is to be remembered that the impossibility of proper administration for the Galactic Empire under the uninspired leadership of the later Emperors was a considerable factor in the Fall.) Daily, fleets of ships in the tens of thousands brought the produce of twenty agricultural worlds to the dinner tables of Trantor."

Foundation has added another element to this mix, a sky bridge that connects Trantor to an orbital docking station - presumably meaning either the station is in geosynchronous orbit, or the very orbit of Trantor around its star has been halted by the advanced science of the Empire. Spaceships arrive on the space station, and passengers are ferried down a massive elevator to the planet's surface. The sheer scale of this engineering feat testifies to the wealth and creativity of the Empire, and to their mastery over their environment.

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The Planets in Foundation

Foundation Salvor Hardin Vault

Foundation's first two episodes introduce a number of different planets, although they're not fleshed out in much detail at this point - and some appear to have been heavily redesigned for David Goyer's TV series in order to make them more distinctive. Gaal Dornick's homeworld, Synnax, has become a waterworld that appears remote and almost religiously unconnected to the rest of the Galaxy, so much so that (unlike the books) Gaal has never been in a Jump Ship before. Meanwhile, conflict between two worlds on the galactic rim leads to representatives of Anacreon and Thespis being summoned to Trantor; the Anacreons become a recurring force in Asimov's books, although the people of Thespis appear original to the TV series.

The other key planet in Foundation is Terminus, situated at the edge of the Galaxy - and chosen by the Empire as the site of Hari Seldon's exile. This barren and uninhabited world is nonetheless able to maintain life, and the Emperor believes it a fitting place to send Seldon so he can't cause any more trouble. Of course, ironically the Emperor has been outsmarted by Seldon, who predicted that he and his followers would be sent to Terminus. When the colonists arrived, they found a mysterious Vault waiting for them on Terminus; in the books, this Vault was a secret repository of knowledge sent by Seldon himself.

Foundation's Psychohistory Explained

Hari Seldon and Gaal Dornik stand side by side in Foundation

Foundation introduces viewers to several low-concept sci-fi ideas, although ironically many - such as Jump Drives - will be familiar to modern audiences because they were absorbed into science-fiction and became standard parts of the lore. The one unique idea in Foundation, though, is a science called "psychohistory" that has been mastered by Hari Seldon, which allows a sufficiently gifted mathematician to predict the future with an incredible degree of accuracy. In his books, Asimov defines psychohistory as "that branch of mathematics which deals with the reactions of human conglomerates to fixed social and economic stimuli," and only two people seem to be capable of understanding psychohistorical theorems to any high degree of certainty - Hari Seldon and Gaal Dornick.

It's important to note that psychohistory does not mean there is no free will; it is of limited use when it comes to predicting the actions of individuals. But it does, however, successfully predict the actions of social groups, meaning it can predict the great movements of history. A sample size needs to be large enough to make it work, and Seldon tested psychohistory on the population of individual planets before looking at the galaxy as a whole. Psychohistory is the driver of the entire Foundation arc, because it is through the development of psychohistory that Seldon has become aware of the coming Dark Ages. He has dedicated himself to reducing the length of these Dark Ages through the establishing of his Foundation on Terminus, and it is likely everything he did - including his public discussion of his predictions - was in order to manipulate events according to his calculations.

David Goyer and his team have chosen to avoid representing psychohistory using any identifiable form of mathematics, instead attempting to create something that looks absolutely beautiful. Goyer's focus was on trying to create an almost religious aesthetic around psychohistory, and in interviews he described it as "the language of angels." By this reading, Seldon is the high priest and prophet of psychohistory, and Foundation is the story of his followers.

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