In physics, action at a distance
is the concept that an object can be moved, changed, or otherwise
affected without being physically touched (as in mechanical contact) by
another object. That is, it is the non-local interaction of objects that
are separated in space.
More generally "action at a distance" describes the failure of early atomistic and mechanistic theories
which sought to reduce all physical interaction to collision. The
exploration and resolution of this problematic phenomenon led to
significant developments in physics, from the concept of a field, to
descriptions of quantum entanglement and the mediator particles of the Standard Model.
Electricity and magnetism
Philosopher William of Ockham discussed action at a distance to explain magnetism and the ability of the Sun to heat the Earth's atmosphere without affecting the intervening space.
Efforts to account for action at a distance in the theory of electromagnetism led to the development of the concept of a field which mediated interactions between currents and charges across empty space. According to field theory, we account for the Coulomb (electrostatic) interaction between charged particles through the fact that charges produce around themselves an electric field, which can be felt by other charges as a force. Maxwell directly addressed the subject of action-at-a-distance in chapter 23 of his A Treatise on Electricity and Magnetism in 1873. He began by reviewing the explanation of Ampère's formula given by Gauss and Weber.
On page 437 he indicates the physicists' disgust with action at a
distance. In 1845 Gauss wrote to Weber desiring "action, not
instantaneous, but propagated in time in a similar manner to that of
light". This aspiration was developed by Maxwell with the theory of an electromagnetic field described by Maxwell's equations,
which used the field to elegantly account for all electromagnetic
interactions, now also including light (which, until then, had only been
suspected as a related phenomenon). In Maxwell's theory, the field is
its own physical entity, carrying momenta and energy across space, and
action-at-a-distance is only the apparent effect of local interactions
of charges with their surrounding field.
Electrodynamics was later described without fields (in Minkowski space) as the direct interaction of particles with lightlike separation vectors.
This resulted in the Fokker-Tetrode-Schwarzschild action integral. This
kind of electrodynamic theory is often called "direct interaction" to
distinguish it from field theories where action at a distance is
mediated by a localized field (localized in the sense that its dynamics
are determined by the nearby field parameters).
This description of electrodynamics, in contrast with Maxwell's theory,
explains apparent action at a distance not by postulating a mediating
entity (a field) but by appealing to the natural geometry of special
relativity.
Direct interaction electrodynamics is explicitly symmetrical in
time and avoids the infinite energy predicted in the field immediately
surrounding point particles. Feynman and Wheeler have shown that it can
account for radiation and radiative damping
(which had been considered strong evidence for the independent
existence of the field). However, various proofs, beginning with that of
Dirac, have shown that direct interaction theories (under reasonable assumptions) do not admit Lagrangian or Hamiltonian formulations (these are the so-called No Interaction Theorems). Also significant is the measurement and theoretical description of the Lamb shift
which strongly suggests that charged particles interact with their own
field. Fields, because of these and other difficulties, have been
elevated to the fundamental operators in Quantum Field Theory and Modern physics has thus largely abandoned direct interaction theory.
Newton's
classical theory of gravity offered no prospect of identifying any
mediator of gravitational interaction. His theory assumed that
gravitation acts instantaneously, regardless of distance. Kepler's
observations gave strong evidence that in planetary motion angular
momentum is conserved. (The mathematical proof is valid only in the case
of a Euclidean geometry.) Gravity is also known as a force of attraction between two objects because of their mass.
From a Newtonian perspective, action at a distance can be
regarded as "a phenomenon in which a change in intrinsic properties of
one system induces a change in the intrinsic properties of a distant
system, independently of the influence of any other systems on the
distant system, and without there being a process that carries this
influence contiguously in space and time" (Berkovitz 2008).
A related question, raised by Ernst Mach,
was how rotating bodies know how much to bulge at the equator. This, it
seems, requires an action-at-a-distance from distant matter, informing
the rotating object about the state of the universe. Einstein coined the
term Mach's principle for this question.
It is inconceivable that inanimate
Matter should, without the Mediation of something else, which is not
material, operate upon, and affect other matter without mutual
Contact…That Gravity should be innate, inherent and essential to Matter,
so that one body may act upon another at a distance thro' a Vacuum,
without the Mediation of any thing else, by and through which their
Action and Force may be conveyed from one to another, is to me so great
an Absurdity that I believe no Man who has in philosophical Matters a
competent Faculty of thinking can ever fall into it. Gravity must be
caused by an Agent acting constantly according to certain laws; but
whether this Agent be material or immaterial, I have left to the
Consideration of my readers.
— Isaac Newton, Letters to Bentley, 1692/3
Different authors have attempted to clarify the aspects of remote action and God’s involvement on the basis of textual investigations, mainly from the Mathematical Principles of Natural Philosophy, Newton’s correspondence with Richard Bentley (1692/93), and Queries that Newton introduced at the end of the Opticks book in the first three editions (between 1704 and 1721).
Andrew Janiak, in Newton as philosopher, considered that Newton denied that gravity
could be essential to matter, dismissed direct action at a distance,
and also rejected the idea of a material substance. But Newton agreed,
in Janiak’s view, with an immaterial ether, which he considered that Newton identifies himself with God
himself: “Newton obviously thinks that God might be the very
“immaterial medium” underlying all gravitational interactions among
material bodies.”
Steffen Ducheyne, in Newton on Action at a Distance, considered that Newton never accepted direct remote action, only material intervention or immaterial substance.
Hylarie Kochiras, in Gravity and Newton’s substance counting problem,
argued that Newton was inclined to reject direct action, giving
priority to the hypothesis of an intangible environment. But, in his
speculative moments, Newton oscillated between accepting and rejecting
direct remote action. Newton, according to Kochiras, claims that God
is a virtual omnipresent, the force/agent must subsist in substance,
and God is omnipresent substantially, resulting in a hidden premise, the
principle of local action.
Eric Schliesser, in Newton’s substance monism, distant action, and the nature of Newton’s Empiricism,
argued that Newton does not categorically refuse the idea that matter
is active, and therefore accepted the possibility of a direct action at a
distance. Newton affirms the virtual omnipresence of God in addition to
his substantial omnipresence.
John Henry, in Gravity and De gravitatione: The Development of Newton’s Ideas on Action at a Distance,
also argued that direct remote action was not inconceivable for Newton,
rejecting the idea that gravity can be explained by subtle matter,
accepting the idea of an omnipotent God, and rejecting the Epicurean attraction.
For further discussion see Ducheyne, S. "Newton on Action at a Distance". Journal of the History of Philosophy vol. 52.4 (2014): 675–702.
Einstein
According to Albert Einstein's theory of special relativity, instantaneous action at a distance violates the relativistic upper limit on speed
of propagation of information. If one of the interacting objects were
to suddenly be displaced from its position, the other object would feel
its influence instantaneously, meaning information had been transmitted
faster than the speed of light.
One of the conditions that a relativistic theory of gravitation
must meet is that gravity is mediated with a speed that does not exceed c,
the speed of light in a vacuum. From the previous success of
electrodynamics, it was foreseeable that the relativistic theory of
gravitation would have to use the concept of a field, or something similar.
This has been achieved by Einstein's theory of general relativity,
in which gravitational interaction is mediated by deformation of
space-time geometry. Matter warps the geometry of space-time, and these
effects are—as with electric and magnetic fields—propagated at the speed
of light. Thus, in the presence of matter, space-time becomes non-Euclidean, resolving the apparent conflict between Newton's proof of the conservation of angular momentum and Einstein's theory of special relativity.
Mach's question regarding the bulging of rotating bodies is
resolved because local space-time geometry is informing a rotating body
about the rest of the universe. In Newton's theory of motion, space acts
on objects, but is not acted upon. In Einstein's theory of motion,
matter acts upon space-time geometry, deforming it; and space-time
geometry acts upon matter, by affecting the behavior of geodesics.
Since the early twentieth century, quantum mechanics has posed new challenges for the view that physical processes should obey locality. Whether quantum entanglement counts as action-at-a-distance hinges on the nature of the wave function and decoherence, issues over which there is still considerable debate among scientists and philosophers.
One important line of debate originated with Einstein, who
challenged the idea that quantum mechanics offers a complete description
of reality, along with Boris Podolsky and Nathan Rosen. They proposed a thought experiment involving an entangled pair of observables with non-commuting operators (e.g. position and momentum).
This thought experiment, which came to be known as the EPR paradox,
hinges on the principle of locality. A common presentation of the
paradox is as follows: two particles interact and fly off in opposite
directions. Even when the particles are so far apart that any classical
interaction would be impossible (see principle of locality), a measurement of one particle nonetheless determines the corresponding result of a measurement of the other.
After the EPR paper, several scientists such as de Broglie studied local hidden variables theories. In the 1960s John Bell derived an inequality that indicated a testable difference between the predictions of quantum mechanics and local hidden variables theories. To date, all experiments
testing Bell-type inequalities in situations analogous to the EPR
thought experiment have results consistent with the predictions of
quantum mechanics, suggesting that local hidden variables theories can
be ruled out. Whether or not this is interpreted as evidence for nonlocality depends on one's interpretation of quantum mechanics.
Interpretations of quantum mechanics vary in their response to the EPR-type experiments. The Bohm interpretation gives an explanation based on nonlocal hidden variables for the correlations seen in entanglement. Many advocates of the many-worlds interpretation argue that it can explain these correlations in a way that does not require a violation of locality, by allowing measurements to have non-unique outcomes.
If "action" is defined as a force, physical work or information, then it should be stated clearly that entanglement
cannot communicate action between two entangled particles (Einstein's
worry about "spooky action at a distance" does not actually violate special relativity).
What happens in entanglement is that a measurement on one entangled
particle yields a random result, then a later measurement on another
particle in the same entangled (shared) quantum state must always yield a
value correlated with the first measurement. Since no force, work, or
information is communicated (the first measurement is random), the speed of light limit does not apply. In the standard Copenhagen interpretation, as discussed above, entanglement demonstrates a genuine nonlocal effect of quantum mechanics, but does not communicate information, either quantum or classical.
Alternate history (also alternative history, althist, AH) is a genre of speculative fiction of stories in which one or more historical events occur and are resolved differently than in real life. As conjecture based upon historical fact, alternative history stories propose What if?
scenarios about crucial events in human history, and present outcomes
very different from the historical record. Alternate history also is a
subgenre of literary fiction, science fiction, and historical fiction; as literature, alternate history uses the tropes of the genre to answer the What if? speculations of the story.
Since the 1950s, as a subgenre of science fiction, alternative history stories feature the tropes of time travel
between histories, and the psychic awareness of the existence of an
alternative universe, by the inhabitants of a given universe; and time
travel that divides history into various timestreams. In the Spanish, French, German, and Portuguese, Italian, Catalan, and Galician languages, the terms Uchronie, ucronia, ucronía, and Uchronie identify the alternate history genre, from which derives the English term Uchronia, composed of the Greek prefix ου- ("not", "not any", and "no") and the Greek word χρόνος (chronos) "time", to describe a story that occurs "[in] no time"; analogous to a story that occurs in utopia, "[in] no place". The term Uchronia also is the name of the list of alternate-history books, uchronia.net. Moreover, Allohistory (other history) is another term for the genre of alternative history.
Definition
Alternative
history is a genre of fiction wherein the author speculates upon how
the course of history might have been altered if a particular historical
event had an outcome different from the real life outcome.
An alternate history requires three conditions: (i) A point of
divergence from the historical record, before the time in which the
author is writing; (ii) A change that would alter known history; and
(iii) An examination of the ramifications of that alteration to history. Occasionally, some types of genre fiction are misidentified as alternative history,
specifically science fiction stories set in a time that was the future
for the writer, but now is the past for the reader, such as the novels 2001: A Space Odyssey (1968), by Arthur C. Clarke and Nineteen Eighty-Four (1949), by George Orwell, because the authors did not alter the history of the past when they wrote the stories.
Moreover, the genre of the Secret History
of an event, which can be either fictional or non-fictional, documents
events that might have occurred in history, but which had no effect upon
the recorded historical outcome. Alternative history also is thematically related to, but distinct from, Counterfactual History, which is a form of historiography that attempts to answer the What if? speculations that arise from counterfactual conditions in order to understand what did happen.
As a method of historical research, counterfactual history explores
historical events with an extrapolated timeline in which key historical
events either did not occur or had an outcome different from the
historical record.
The earliest example of alternate (or counterfactual) history is found in Livy's Ab Urbe Condita Libri (book IX, sections 17–19). Livy contemplated an alternative 4th century BC in which Alexander the Great had survived to attack Europe as he had planned; asking, "What would have been the results for Rome if she had been engaged in a war with Alexander?" Livy concluded that the Romans would likely have defeated Alexander. An even earlier possibility is Herodotus's Histories, which contains speculative material.
Another example of counterfactual history was posited by cardinal and Doctor of the ChurchPeter Damian in the 11th century. In his famous work De Divina Omnipotentia, a long letter in which he discusses God's omnipotence, he treats questions related to the limits of divine power, including the question of whether God can change the past, for example, bringing about that Rome was never founded:
I
see I must respond finally to what many people, on the basis of your
holiness’s [own] judgment, raise as an objection on the topic of this
dispute. For they say: If, as you assert, God is omnipotent in all
things, can he manage this, that things that have been made were not
made? He can certainly destroy all things that have been made, so that
they do not exist now. But it cannot be seen how he can bring it about
that things that have been made were not made. To be sure, it can come
about that from now on and hereafter Rome does not exist; for it can be
destroyed. But no opinion can grasp how it can come about that it was
not founded long ago...
One early work of fiction detailing an alternate history is Joanot Martorell's 1490 epicromanceTirant lo Blanch, which was written when the loss of Constantinople to the Turks was still a recent and traumatic memory for Christian Europe. It tells the story of the knight Tirant the White from Brittany who travels to the embattled remnants of the Byzantine Empire. He becomes a Megaduke and commander of its armies and manages to fight off the invading Ottoman armies of Mehmet II. He saves the city from Islamic conquest, and even chases the Turks deeper into lands they had previously conquered.
19th century
One of the earliest works of alternate history published in large quantities for the reception of a large audience may be Louis Geoffroy's Histoire de la Monarchie universelle: Napoléon et la conquête du monde (1812–1832) (History of the Universal Monarchy: Napoleon and the Conquest of the World) (1836), which imagines Napoleon's First French Empire emerging victorious in the French invasion of Russia in 1811 and in an invasion of England in 1814, later unifying the world under Bonaparte's rule.
The first novel-length alternate history in English would seem to be Castello Holford's Aristopia (1895). While not as nationalistic as Louis Geoffroy's Napoléon et la conquête du monde, 1812–1823, Aristopia is another attempt to portray a Utopian society. In Aristopia, the earliest settlers in Virginia discover a reef made of solid gold and are able to build a Utopian society in North America.
Early 20th century and the era of the pulps
In 1905, H. G. Wells published A Modern Utopia.
As explicitly noted in the book itself, Wells's main aim in writing it
was to set out his social and political ideas, the plot serving mainly
as a vehicle to expound them. This book introduced the idea of a person
being transported from a point in our familiar world to the precise
geographical equivalent point in an alternate world in which history had
gone differently. The protagonists undergo various adventures in the
alternate world, and then are finally transported back to our world,
again to the precise geographical equivalent point. Since then, that has
become a staple of the alternate history genre.
A number of alternate history stories and novels appeared in the late 19th and early 20th centuries (see, for example, Joseph Edgar Chamberlin's The Ifs of History [1907] and Charles Petrie's If: A Jacobite Fantasy [1926]). In 1931, British historian Sir John Squire collected a series of essays from some of the leading historians of the period for his anthology If It Had Happened Otherwise.
In that work, scholars from major universities, as well as important
non-academic authors, turned their attention to such questions as "If
the Moors in Spain Had Won" and "If Louis XVI Had Had an Atom of Firmness". The essays range from serious scholarly efforts to Hendrik Willem van Loon's fanciful and satiric portrayal of an independent 20th-century New Amsterdam, a Dutch city-state on the island of Manhattan. Among the authors included were Hilaire Belloc, André Maurois, and Winston Churchill.
One of the entries in Squire's volume was Churchill's "If Lee Had
Not Won the Battle of Gettysburg", written from the viewpoint of a
historian in a world in which the Confederacy had won the American Civil War.
The entry considers what would have happened if the North had been
victorious (in other words, a character from an alternate world imagines
a world more like the real one we live in, although it is not identical
in every detail). Speculative work that narrates from the point of view
of an alternate history is variously known as "recursive alternate history", a "double-blind what-if", or an "alternate-alternate history". Churchill's essay was one of the influences behind Ward Moore's alternate history novel Bring the Jubilee in which General Robert E. Lee won the Battle of Gettysburg
and paved the way for the eventual victory of the Confederacy in the
American Civil War (named the "War of Southron Independence" in this
timeline). The protagonist, the autodidact Hodgins Backmaker, travels
back to the aforementioned battle and inadvertently changes history,
which results in the emergence of our own timeline and the consequent
victory of the Union instead.
The American humorist author James Thurber
parodied alternate history stories about the American Civil War in his
1930 story "If Grant Had Been Drinking at Appomattox", which he
accompanied with this very brief introduction: "Scribner's
magazine is publishing a series of three articles: 'If Booth Had Missed
Lincoln', 'If Lee Had Won the Battle of Gettysburg', and 'If Napoleon
Had Escaped to America'. This is the fourth".
Another example of alternate history from this period (and arguably the first that explicitly posited cross-time travel from one universe to another as anything more than a visionary experience) is H.G. Wells' Men Like Gods (1923) in which the London-based journalist
Mr. Barnstable, along with two cars and their passengers, is
mysteriously teleported into "another world", which the "Earthlings"
call Utopia. Being far more advanced than Earth, Utopia is some 3000
years ahead of humanity in its development. Wells describes a multiverse
of alternative worlds, complete with the paratime travel machines that
would later become popular with American pulp writers. However, since
his hero experiences only a single alternate world, the story is not
very different from conventional alternate history.
In the 1930s, alternate history moved into a new arena. The December 1933 issue of Astounding published Nat Schachner's "Ancestral Voices", which was quickly followed by Murray Leinster's "Sidewise in Time".
While earlier alternate histories examined reasonably-straightforward
divergences, Leinster attempted something completely different. In his
"World gone mad", pieces of Earth traded places with their analogs from
different timelines. The story follows Professor Minott and his students
from a fictitious Robinson College as they wander through analogues of
worlds that followed a different history.
A somewhat similar approach was taken by Robert A. Heinlein in his 1941 novelette Elsewhen
in which a professor trains his mind to move his body across timelines.
He then hypnotizes his students so that they can explore more of them.
Eventually, each settles into the reality that is most suitable for him
or her. Some of the worlds they visit are mundane, some are very odd,
and others follow science fiction or fantasy conventions.
World War II produced alternate history for propaganda: both British and American authors wrote works depicting Nazi invasions of their respective countries as cautionary tales.
Time travel to create historical divergences
The period around World War II also saw the publication of the time travel novel Lest Darkness Fall by L. Sprague de Camp in which an American academic travels to Italy at the time of the Byzantine invasion of the Ostrogoths.
De Camp's time traveler, Martin Padway, is depicted as making permanent
historical changes and implicitly forming a new time branch, thereby
making the work an alternate history.
In William Tenn's short story Brooklyn Project
(1948), a tyrannical US Government brushes aside the warnings of
scientists about the dangers of time travel and goes on with a planned
experiment - with the result that minor changes to the prehistoric past
cause Humanity to never have existed, its place taken by tentacled
underwater intelligent creatures - who also have a tyrannical government
which also insists on experimenting with time-travel.
Time travel as the cause of a point of divergence
(POD), which can denote either the bifurcation of a historical timeline
or a simple replacement of the future that existed before the
time-travelling event, has continued to be a popular theme. In Ward
Moore's Bring the Jubilee, the protagonist lives in an alternate
history in which the Confederacy has won the American Civil War. He
travels backward through time and brings about a Union victory at the
Battle of Gettysburg.
When a story's assumptions about the nature of time travel lead
to the complete replacement of the visited time's future, rather than
just the creation of an additional time line, the device of a "time
patrol" is often used where guardians move through time to preserve the
"correct" history.
A more recent example is Making History by Stephen Fry in which a time machine is used to alter history so that Adolf Hitler was never born. That ironically results in a more competent leader of Nazi Germany and results in the country's ascendancy and longevity in the altered timeline.
Cross-time stories
H.G. Wells' "cross-time" or "many universes" variant (see above) was
fully developed by Murray Leinster in his 1934 short story "Sidewise in
Time", in which sections of the Earth's surface begin changing places
with their counterparts in alternate timelines.
Fredric Brown
employed this subgenre to satirize the science fiction pulps and their
adolescent readers—and fears of foreign invasion—in the classic What Mad Universe (1949). In Clifford D. Simak's Ring Around the Sun
(1953), the hero ends up in an alternate earth of thick forests in
which humanity never developed but a band of mutants is establishing a
colony; the story line appears to frame the author's anxieties regarding
McCarthyism and the Cold War.
Quantum theory of many worlds
While many justifications for alternate histories involve a multiverse, the "many world" theory
would naturally involve many worlds, in fact a continually exploding
array of universes. In quantum theory, new worlds would proliferate with
every quantum event, and even if the writer uses human decisions, every
decision that could be made differently would result in a different
timeline. A writer's fictional multiverse may, in fact, preclude some
decisions as humanly impossible, as when, in Night Watch, Terry Pratchett
depicts a character informing Vimes that while anything that can
happen, has happened, nevertheless there is no history whatsoever in
which Vimes has ever murdered his wife. When the writer explicitly
maintains that all possible decisions are made in all possible
ways, one possible conclusion is that the characters were neither brave,
nor clever, nor skilled, but simply lucky enough to happen on the
universe in which they did not choose the cowardly route, take the
stupid action, fumble the crucial activity, etc.; few writers focus on
this idea, although it has been explored in stories such as Larry Niven's story All the Myriad Ways,
where the reality of all possible universes leads to an epidemic of
suicide and crime because people conclude their choices have no moral
import.
In any case, even if it is true that every possible outcome
occurs in some world, it can still be argued that traits such as bravery
and intelligence might still affect the relative frequency of worlds in
which better or worse outcomes occurred (even if the total number of
worlds with each type of outcome is infinite, it is still possible to
assign a different measure to different infinite sets). The physicist David Deutsch,
a strong advocate of the many-worlds interpretation of quantum
mechanics, has argued along these lines, saying that "By making good
choices, doing the right thing, we thicken the stack of universes in
which versions of us live reasonable lives. When you succeed, all the
copies of you who made the same decision succeed too. What you do for
the better increases the portion of the multiverse where good things
happen."
This view is perhaps somewhat too abstract to be explored directly in
science fiction stories, but a few writers have tried, such as Greg Egan in his short story The Infinite Assassin,
where an agent is trying to contain reality-scrambling "whirlpools"
that form around users of a certain drug, and the agent is constantly
trying to maximize the consistency of behavior among his alternate
selves, attempting to compensate for events and thoughts he experiences,
he guesses are of low measure relative to those experienced by most of
his other selves.
Many writers—perhaps the majority—avoid the discussion entirely. In one novel of this type, H. Beam Piper's Lord Kalvan of Otherwhen,
a Pennsylvania State Police officer, who knows how to make gunpowder,
is transported from our world to an alternate universe where the recipe
for gunpowder is a tightly held secret and saves a country that is about
to be conquered by its neighbors. The paratime patrol members are
warned against going into the timelines immediately surrounding it,
where the country will be overrun, but the book never depicts the
slaughter of the innocent thus entailed, remaining solely in the
timeline where the country is saved.
The cross-time theme was further developed in the 1960s by Keith Laumer in the first three volumes of his Imperium sequence, which would be completed in Zone Yellow (1990). Piper's politically more sophisticated variant was adopted and adapted by Michael Kurland and Jack Chalker in the 1980s; Chalker's G.O.D. Inc
trilogy (1987–89), featuring paratime detectives Sam and Brandy
Horowitz, marks the first attempt at merging the paratime thriller with
the police procedural. Kurland's Perchance
(1988), the first volume of the never-completed "Chronicles of
Elsewhen", presents a multiverse of secretive cross-time societies that
utilize a variety of means for cross-time travel, ranging from high-tech
capsules to mutant powers. Harry Turtledove has launched the Crosstime Traffic series for teenagers featuring a variant of H. Beam Piper's paratime trading empire.
Rival paratime worlds
The concept of a cross-time version of a world war, involving rival paratime empires, was developed in Fritz Leiber's Change War series, starting with the Hugo Award winning The Big Time (1958); followed by Richard C. Meredith's Timeliner trilogy in the 1970s, Michael McCollum's A Greater Infinity (1982) and John Barnes'Timeline Wars trilogy in the 1990s.
Such "paratime" stories may include speculation that the laws of
nature can vary from one universe to the next, providing a science
fictional explanation—or veneer—for what is normally fantasy. Aaron Allston's Doc Sidhe and Sidhe Devil
take place between our world, the "grim world" and an alternate "fair
world" where the Sidhe retreated to. Although technology is clearly
present in both worlds, and the "fair world" parallels our history,
about fifty years out of step, there is functional magic in the fair
world. Even with such explanation, the more explicitly the alternate
world resembles a normal fantasy world, the more likely the story is to
be labelled fantasy, as in Poul Anderson's "House Rule" and "Loser's
Night". In both science fiction and fantasy, whether a given parallel
universe is an alternate history may not be clear. The writer might
allude to a POD only to explain the existence and make no use of the
concept, or may present the universe without explanation of its
existence.
Major writers explore alternate histories
Isaac Asimov's short story "What If—"
(1952) is about a couple who can explore alternate realities by means
of a television-like device. This idea can also be found in Asimov's
novel The End of Eternity (1955), in which the "Eternals" can change the realities of the world, without people being aware of it. Poul Anderson's Time Patrol stories feature conflicts between forces intent on changing history and the Patrol who work to preserve it. One story, Delenda Est, describes a world in which Carthage triumphed over the Roman Republic. The Big Time, by Fritz Leiber, describes a Change War ranging across all of history.
Keith Laumer's Worlds of the Imperium is one of the earliest alternate history novels; it was published by Fantastic Stories of the Imagination in 1961, in magazine form, and reprinted by Ace Books in 1962 as one half of an Ace Double.
Besides our world, Laumer describes a world ruled by an Imperial
aristocracy formed by the merger of European empires, in which the American Revolution never happened, and a third world in post-war chaos ruled by the protagonist's doppelganger.
Philip K. Dick's novel, The Man in the High Castle
(1962), is an alternate history in which Nazi Germany and Imperial
Japan won World War II. This book contains an example of
"alternate-alternate" history, in that one of its characters authored a
book depicting a reality in which the Allies won the war, itself
divergent from real-world history in several aspects. The several
characters live within a divided United States, in which the Empire of Japan takes the Pacific states, governing them as a puppet, Nazi Germany takes the East Coast of the United States and parts of the Midwest, with the remnants of the old United States' government as the Neutral Zone, a buffer state between the two superpowers. The book has inspired an Amazon series of the same name.
Vladimir Nabokov's novel, Ada or Ardor: A Family Chronicle (1969), is a story of incest that takes place within an alternate North America settled in part by Czarist Russia
and that borrows from Dick's idea of "alternate-alternate" history (the
world of Nabokov's hero is wracked by rumors of a "counter-earth" that
apparently is ours). Some critics believe that the references to a counter-earth suggest that the world portrayed in Ada is a delusion in the mind of the hero (another favorite theme of Dick's novels). Strikingly, the characters in Ada
seem to acknowledge their own world as the copy or negative version,
calling it "Anti-Terra", while its mythical twin is the real "Terra".
Like history, science has followed a divergent path on Anti-Terra: it
boasts all the same technology as our world, but all based on water
instead of electricity; e.g., when a character in Ada makes a long-distance call, all the toilets in the house flush at once to provide hydraulic power.
Guido Morselli described the defeat of Italy (and subsequently France) in World War I in his novel, Past Conditional (1975; Contro-passato prossimo), wherein the static Alpine front
line which divided Italy from Austria during that war collapses when
the Germans and the Austrians forsake trench warfare and adopt
blitzkrieg twenty years in advance.
Kingsley Amis set his novel, The Alteration
(1976), in the 20th century, but major events in the Reformation did
not take place, and Protestantism is limited to the breakaway Republic
of New England. Martin Luther was reconciled to the Roman Catholic Church and later became Pope Germanian I.
Kim Stanley Robinson's novel, The Years of Rice and Salt (2002), starts at the point of divergence with Timur turning his army away from Europe, and the Black Death has killed 99% of Europe's population, instead of only a third. Robinson explores world history from that point in AD 1405 (807 AH) to about AD 2045 (1467 AH). Rather than following the great man theory of history, focusing on leaders, wars, and major events, Robinson writes more about social history, similar to the Annales School of history theory and Marxist historiography, focusing on the lives of ordinary people living in their time and place.
Michael Chabon, occasionally an author of speculative fiction, contributed to the genre with his novel The Yiddish Policemen's Union (2007), which explores a world in which the State of Israel
was destroyed in its infancy and many of the world's Jews instead live
in a small strip of Alaska set aside by the US government for Jewish
settlement. The story follows a Jewish detective solving a murder case
in the Yiddish-speaking semi-autonomous city state of Sitka. Stylistically, Chabon borrows heavily from the noir
and detective fiction genres, while exploring social issues related to
Jewish history and culture. Apart from the alternate history of the Jews
and Israel, Chabon also plays with other common tropes of alternate
history fiction; in the book, Germany actually loses the war even harder
than they did in reality, getting hit with a nuclear bomb instead of
just simply losing a ground war (subverting the common "what if Germany
won WWII?" trope).
Contemporary alternate history in popular literature
The late 1980s and the 1990s saw a boom in popular-fiction versions
of alternate history, fueled by the emergence of the prolific alternate
history author Harry Turtledove, as well as the development of the steampunk genre and two series of anthologies—the What Might Have Been series edited by Gregory Benford and the Alternate ... series edited by Mike Resnick. This period also saw alternate history works by S. M. Stirling, Kim Stanley Robinson, Harry Harrison, Howard Waldrop, Peter Tieryas, and others.
In 1986, a sixteen-part epic comic book series called Captain Confederacy began examining a world where the Confederate States of America won the American Civil War. In the series, the Captain and others heroes are staged government propaganda events featuring the feats of these superheroes.
Perhaps the most incessantly explored theme in popular alternate history focuses on worlds in which the Nazis won World War Two. In some versions, the Nazis and/or Axis Powers
conquer the entire world; in others, they conquer most of the world but
a "Fortress America" exists under siege; while in others, there is a
Nazi/Japanese Cold War comparable to the US/Soviet equivalent in 'our' timeline. Fatherland (1992), by Robert Harris, is set in Europe following the Nazi victory. The novel Dominion by C.J. Sansom
(2012) is similar in concept but is set in England, with Churchill the
leader of an anti-German Resistance and other historic persons in
various fictional roles. In the Mecha Samurai Empire series (2016), Peter Tieryas
focuses on the Asian-American side of the alternate history, exploring
an America ruled by the Japanese Empire while integrating elements of
Asian pop culture like mechas and videogames.
Several writers have posited points of departure for such a world
but then have injected time splitters from the future or paratime
travel, for instance James P. Hogan's The Proteus Operation. Norman Spinrad wrote The Iron Dream in 1972, which is intended to be a science fiction novel written by Adolf Hitler after fleeing from Europe to North America in the 1920s.
In Jo Walton's
"Small Change" series, the United Kingdom made peace with Hitler before
the involvement of the United States in World War II, and slowly
collapses due to severe economic depression. Former House Speaker Newt Gingrich and William R. Forstchen have written a novel, 1945, in which the US defeated Japan but not Germany
in World War II, resulting in a Cold War with Germany rather than the
Soviet Union. Gingrich and Forstchen neglected to write the promised
sequel; instead, they wrote a trilogy about the American Civil War,
starting with Gettysburg: A Novel of the Civil War, in which the Confederates win a victory at the Battle of Gettysburg
- however, after Lincoln responds by bringing Grant and his forces to
the eastern theater, the Army of Northern Virginia is soon trapped and
destroyed in Maryland, and the war ends within weeks. Also from that
general era, Martin Cruz Smith, in his first novel, posited an independent American Indian nation following the defeat of Custer in The Indians Won (1970).
A recent time traveling splitter variant involves entire
communities being shifted elsewhere to become the unwitting creators of
new time branches. These communities are transported from the present
(or the near-future) to the past or to another time-line via a natural
disaster, the action of technologically advanced aliens, or a human
experiment gone wrong. S. M. Stirling wrote the Island in the Sea of Time trilogy, in which Nantucket Island and all its modern inhabitants are transported to Bronze Age times to become the world's first superpower. In Eric Flint's 1632 series, a small town in West Virginia is transported to 17th century central Europe and drastically changes the course of the Thirty Years' War, which was then underway. John Birmingham's Axis of Time
trilogy deals with the culture shock when a United Nations naval task
force from 2021 finds itself back in 1942 helping the Allies against the
Empire of Japan and the Germans (and doing almost as much harm as good in spite of its advanced weapons). Similarly, Robert Charles Wilson's Mysterium
depicts a failed US government experiment which transports a small
American town into an alternative version of the US run by believers in a
form of Christianity known as Gnosticism,
who are engaged in a bitter war with the "Spanish" in Mexico (the chief
scientist at the laboratory where the experiment occurred is described
as a Gnostic, and references to Christian Gnosticism appear repeatedly
in the book). In Time for Patriots by retired astronomer Thomas Wm. Hamilton (4897 Tomhamilton) a town and military academy on Long Island are transported back to 1770, where they shorten the American Revolution, rewrite the Constitution, prolong Mozart's life, battle Barbary pirates, and have other adventures.
Although not dealing in physical time travel, in his alt-history novel Marx Returns, Jason Barker introduces anachronisms into the life and times of Karl Marx, such as when his wife Jenny sings a verse from the Sex Pistols's song "Anarchy in the U.K.", or in the games of chess she plays with the Marxes' housekeeper Helene Demuth, which on one occasion involves a Caro–Kann Defence. In her review of the novel, Nina Power
writes of "Jenny’s 'utopian' desire for an end to time", an attitude
which, according to Power, is inspired by her husband's co-authored book
The German Ideology. However, in keeping with the novel's anachronisms, the latter was not published until 1932. By contrast, the novel's timeline ends in 1871.
Many works of straight fantasy and science fantasy take place in historical settings, though with the addition of, for example, magic or mythological beasts. Some present a secret history
in which the modern day world no longer believes that these elements
ever existed. Many ambiguous alternate/secret histories are set in
Renaissance or pre-Renaissance times, and may explicitly include a
"retreat" from the world, which would explain the current absence of
such phenomena. Other stories make plan a divergence of some kind.
Randall Garrett's "Lord Darcy" series presents a point of divergence: a monk systemizes magic rather than science, so the use of foxglove to treat heart disease is regarded as superstition. Another point of divergence occurs in 1199, when Richard the Lionheart survives the Siege of Chaluz and returns to England and makes the Angevin Empire so strong that it survives into the 20th century.
Jonathan Strange & Mr Norrell by Susanna Clarke
takes place in an England where a separate Kingdom ruled by the Raven
King and founded on magic existed in Northumbria for over 300 years. In Patricia Wrede's Regency fantasies, Great Britain has a Royal Society of Wizards.
The Tales of Alvin Maker series by Orson Scott Card
takes place in an alternate America, beginning in the early 19th
century. Prior to that time, a POD occurred: England, under the rule of Oliver Cromwell,
had banished "makers", or anyone else demonstrating "knacks" (an
ability to perform seemingly supernatural feats) to the North American
continent. Thus the early American colonists embraced as perfectly
ordinary these gifts, and counted on them as a part of their daily
lives. The political division of the continent is considerably altered,
with two large English colonies bookending a smaller "American" nation,
one aligned with England, and the other governed by exiled Cavaliers.
Actual historical figures are seen in a much different light: Ben
Franklin is revered as the continent's finest "maker", George Washington
was executed after being captured, and "Tom" Jefferson is the first president of "Appalachia", the result of a compromise between the Continentals and the Crown.
On the other hand, when the "Old Ones" (fairies) still manifest themselves in England in Keith Roberts's Pavane, which takes place in a technologically backward world after a Spanish assassination of Elizabeth I allowed the Spanish Armada
to conquer England, the possibility that the fairies were real but
retreated from modern advances makes the POD possible: the fairies
really were present all along, in a secret history.
Again, in the English Renaissance fantasy Armor of Light by Melissa Scott and Lisa A. Barnett, the magic used in the book, by Dr. John Dee
and others, actually was practiced in the Renaissance; positing a
secret history of effective magic makes this an alternate history with a
point of departure. Sir Philip Sidney survives the Battle of Zutphen in 1586, and shortly thereafter saving the life of Christopher Marlowe.
When the magical version of our world's history is set in
contemporary times, the distinction becomes clear between alternate
history on the one hand and contemporary fantasy, using in effect a form of secret history (as when Josepha Sherman's Son of Darkness has an elf living in New York City, in disguise) on the other. In works such as Robert A. Heinlein's Magic, Incorporated where a construction company can use magic to rig up stands at a sporting event and Poul Anderson's Operation Chaos and its sequel Operation Luna,
where djinns are serious weapons of war—with atomic bombs—the use of
magic throughout the United States and other modern countries makes it
clear that this is not secret history—although references in Operation Chaos to degaussing
the effects of cold iron make it possible that it is the result of a
POD. The sequel clarifies this as the result of a collaboration of
Einstein and Planck in 1901, resulting in the theory of "rhea tics". Henry Moseley applies this theory to "degauss the effects of cold iron and release the goetic forces." This results in the suppression of ferromagnetism and the re-emergence of magic and magical creatures.
Alternate history shades off into other fantasy subgenres
when the use of actual, though altered, history and geography
decreases, although a culture may still be clearly the original source; Barry Hughart's Bridge of Birds and its sequels take place in a fantasy world, albeit one clearly based on China, and with allusions to actual Chinese history, such as the Empress Wu. Richard Garfinkle's Celestial Matters incorporates ancient Chinese physics and Greek Aristotelian physics, using them as if factual.
Alternate history has long been a staple of Japanese speculative fiction with such authors as Futaro Yamada and Ryō Hanmura
writing novels set in recognizable historical settings withaddded
supernatural or science fiction elements. Ryō Hanmura's 1973 Musubi no Yama Hiroku
which recreated 400 years of Japan's history from the perspective of a
secret magical family with psychic abilities. The novel has since come
to be recognized as a masterpiece of Japanese speculative fiction. Twelve years later, author Hiroshi Aramata wrote the groundbreaking Teito Monogatari which reimagined the history of Tokyo across the 20th century in a world heavily influenced by the supernatural.
Television
The TV show Sliders
explores different possible alternate realities by having the
protagonist "slide" into different parallel dimensions of the same
planet Earth. Another TV show Motherland: Fort Salem explores a female-dominated world in which witchcraft is real. Its world diverged from our timeline when the Salem witch trials are resolved by an agreement between witches and ungifted humans.
The TV show The Man in the High Castle is an adaptation of the novel with the same name that ran for four seasons.
Video games
For
the same reasons that this genre is explored by role-playing games,
alternate history is also an intriguing backdrop for the storylines of
many video games. A famous example of an alternate history game is Command & Conquer: Red Alert. Released in 1996, the game presents a point of divergence in 1946 in which Albert Einstein goes back in time to prevent World War II from ever taking place by erasing Adolf Hitler from time after he is released from Landsberg Prison in 1924. Einstein is successful in his mission, but in the process, he allows Joseph Stalin and the Soviet Union to become powerful enough to launch a massive campaign to conquer Europe.
In the Civilization
series, the player guides a civilization from prehistory to the present
and creates radically altered versions of history on a long time scale.
Several scenarios recreate a particular period, which becomes the
"point of divergence" in an alternate history shaped by the player's
actions. Popular examples in Sid Meier's Civilization IV include Desert War, set in the Mediterranean theatre of World War II and featuring scripted events tied to possible outcomes of battles; Broken Star, set in a hypothetical Russian civil war in 2010; and Rhye's and Fall of Civilization,
an 'Earth simulator' designed to mirror a history as closely as
possible but incorporating unpredictable elements to provide realistic
alternate settings.
In some games such as the Metal Gear and Resident Evil
series, events that were originally intended to represent the near
future when the games were originally released later ended up becoming
alternate histories in later entries in those franchises. For example, Metal Gear 2: Solid Snake (1990), set in 1999, depicted a near future that ended up becoming an alternate history in Metal Gear Solid (1998). Likewise, Resident Evil (1996) and Resident Evil 2 (1998), both set in 1998, depicted near-future events that had later become an alternative history by the time Resident Evil 4 (2005) was released.
In the 2009 steampunk shooter, Damnation is set on an alternate version of planet Earth, in the early 20th century after the American Civil War,
which had spanned over several decades, and steam engines replace
combustion engines. The game sees the protagonists fighting off a rich
industrialist who wants to do away with both the Union and the
Confederacy in one swift movement and turn the United States of America into a country called the "American Empire" with a totalitarian dictatorship.
A balkanized 1930s North America from the Crimson Skies franchise
Crimson Skies is one example of an alternate history spawning multiple interpretations in multiple genres. The stories and games in Crimson Skies
take place in an alternate 1930s United States in which the nation
crumbled into many hostile states following the effects of the Great Depression, the Great War, and Prohibition. With the road and railway system destroyed, commerce took to the skies, which led to the emergence of air pirate gangs who plunder the aerial commerce.
The game Freedom Fighters portrays a situation similar to that of the movie Red Dawn and Red Alert 2 but less comically than the latter. The point of divergence is during World War II in which the Soviet Union develops an atomic bomb first and uses it on Berlin.
With the balance of power and influence tipped in Russia's favor,
history diverges. Brief summaries at the beginning of the game inform
the player of the Communist bloc's complete takeover of Europe by 1953, a
different ending to the Cuban Missile Crisis, and the spread of Soviet influence into South America and Mexico.
Similarly, the 2007 video game World in Conflict
is set in 1989, with the Soviet Union on the verge of collapse. The
point of divergence is several months before the opening of the game,
when Warsaw Pact forces staged a desperate invasion of Western Europe. As the game begins, a Soviet invasion force lands in Seattle and takes advantage of the fact that most of the US military is in Europe.
The game Battlestations: Pacific, released in 2008, offered in alternate history campaign for the Imperial Japanese Navy in which Japan destroys all three carriers in the Battle of Midway,
which is followed by a successful invasion of the island. That causes
the United States to lack any sort of aerial power to fight the Japanese
and to be continuously forced onto the defense.
Another alternate history game involving Nazis is War Front: Turning Point
in which Hitler died during the early days of World War II and so a
much more effective leadership rose to power. Under the command of a new
Führer (who is referred to as "Chancellor", with his real name never
being revealed), Operation Sealion succeeds, and the Nazis successfully
conquer Britain and spark a cold war between them and the Allied Powers.
The Fallout series
of computer role-playing games is set in a divergent US, whose history
after World War II diverges from the real world to follow a retro-futuristic timeline. For example, fusion power was invented quite soon after the end of the war, but the transistor
was never developed. The result was a future that has a 1950s "World of
Tomorrow" feel to it, with extremely high technology like artificial intelligence implemented with thermionic valves and other technologies that are now considered obsolete.
Many game series by the Swedish developer Paradox Interactive
start at a concise point in history and allow the player to immerse in
the role of a contemporary leader and alter the course of in-game
history. The most prominent game with that setting is Crusader Kings II.
Wolfenstein: The New Order is set in an alternate 1960 in which the Nazis won World War II and do so also by acquiring high technology. The sequel Wolfenstein II: The New Colossus continues that but is set in the conquered United States of America.
Online
Fans of
alternate history have made use of the internet from a very early point
to showcase their own works and provide useful tools for those fans
searching for anything alternate history, first in mailing lists and usenet
groups, later in web databases and forums. The "Usenet Alternate
History List" was first posted on April 11, 1991, to the Usenet
newsgroup rec.arts.sf-lovers. In May 1995, the dedicated newsgroup soc.history.what-if was created for showcasing and discussing alternate histories. Its prominence declined with the general migration from unmoderated usenet to moderated web forums, most prominently AlternateHistory.com, the self-described "largest gathering of alternate history fans on the internet" with over 10,000 active members.
In addition to these discussion forums, in 1997 Uchronia: The Alternate History List
was created as an online repository, now containing over 2,900
alternate history novels, stories, essays, and other printed materials
in several different languages. Uchronia was selected as the Sci Fi Channel's "Sci Fi Site of the Week" twice.
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