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Monday, May 9, 2022

Self-immolation

From Wikipedia, the free encyclopedia

Self-immolation is the act of sacrificing oneself by setting oneself on fire and burning to death. It is typically used for political or religious reasons, often as a form of non-violent protest or in acts of martyrdom. It has a centuries-long recognition as the most extreme form of protest possible by humankind.

Etymology

The English word immolation originally meant (1534) "killing a sacrificial victim; sacrifice" and came to figuratively mean (1690) "destruction, especially by fire". Its etymology was from Latin immolare "to sprinkle with sacrificial meal (mola salsa); to sacrifice" in ancient Roman religion.

Self-immolation was first recorded in Lady Morgan's France (1817).

Effects

Self-immolators frequently use accelerants before igniting themselves on fire. This, combined with the self-immolators' refusal to protect themselves, can produce hotter flames and deeper, more extensive burns. Most of the time, it leads to amputation of extremities.

Self-immolation has been described as excruciatingly painful. Later the burns become severe, nerves are burnt and the self-immolator loses sensation at the burnt areas. Some self-immolators can die during the act from inhalation of toxic combustion products, hot air and flames. A while later, their body releases adrenaline.

The body has an inflammatory response to burnt skin which happens after 25% is burnt in adults. This response leads to blood and body fluid loss. If the self-immolator is not taken to a burn centre in less than four hours, they are more likely to die from shock. If no more than 80% of their body area is burnt and the self-immolator is younger than 40 years old, there is a survival chance of 50%. If the self-immolator has over 80% burns, the survival rate drops to 20%.

History

The self-immolation (jauhar) of the Rajput women, during the Siege of Chittorgarh in 1568

Self-immolation is tolerated by some elements of Mahayana Buddhism and Hinduism, and it has been practiced for many centuries, especially in India, for various reasons, including jauhar, political protest, devotion, and renouncement. An example from mythology includes the practice of Sati when the Hindu goddess Parvati's incarnation of the same name (see also Daksayani) legendarily set herself on fire after her father insulted her in Daksha Yajna for having married Shiva, the ascetic god. Shiva, Parvati and their army of ghosts attacked Daksha's Yajna and destroyed the sacrifice and Shiva beheaded Daksha and killed Daksha. Later, Daksha was revived by him and Daksha Yajna was completed when Daksha apologized. Certain warrior cultures, such as those of the Charans and Rajputs, also practiced self-immolation.

Zarmanochegas was a monk of the Sramana tradition (possibly, but not necessarily a Buddhist) who, according to ancient historians such as Strabo and Dio Cassius, met Nicholas of Damascus in Antioch around 22 BC and burnt himself to death in Athens shortly thereafter.

The monk Fayu 法羽 (d. 396) carried out the earliest recorded Chinese self-immolation. He first informed the "illegitimate" prince Yao Xu 姚緒—brother of Yao Chang who founded the non-Chinese Qiang state Later Qin (384–417)—that he intended to burn himself alive. Yao tried to dissuade Fayu, but he publicly swallowed incense chips, wrapped his body in oiled cloth, and chanted while setting fire to himself. The religious and lay witnesses were described as being "full of grief and admiration".

Following Fayu's example, many Buddhist monks and nuns have used self-immolation for political purposes. Based upon analysis of Chinese historical records from the 4th to the 20th centuries, some monks did offer their bodies in periods of relative prosperity and peace, but there is a "marked coincidence" between acts of self-immolation and times of crisis, especially when secular powers were hostile towards Buddhism. For example, Daoxuan's (c. 667) Xu Gaoseng Zhuan (續高僧傳, or Continued Biographies of Eminent Monks) records five monastics who self-immolated on the Zhongnan Mountains in response to the 574–577 persecution of Buddhism by Emperor Wu of Northern Zhou (known as the "Second Disaster of Wu").

A Hindu widow burning herself with the corpse of her husband (sati), 1657

For many monks and laypeople in Chinese history, self-immolation was a form of Buddhist practice that modeled and expressed a particular path that led towards Buddhahood.

Historian Jimmy Yu has stated that self-immolation cannot be interpreted based on Buddhist doctrine and beliefs alone but the practice must be understood in the larger context of the Chinese religious landscape. He examines many primary sources from the 16th and 17th century and demonstrates that bodily practices of self-harm, including self-immolation, was ritually performed not only by Buddhists but also by Daoists and literati officials who either exposed their naked body to the sun in a prolonged period of time as a form of self-sacrifice or burned themselves as a method of procuring rain. In other words, self-immolation was a sanctioned part of Chinese culture that was public, scripted, and intelligible both to the person doing the act and to those who viewed and interpreted it, regardless of their various religion affiliations.

During the Great Schism of the Russian Church, entire villages of Old Believers burned themselves to death in an act known as "fire baptism" (self-burners: soshigateli). Scattered instances of self-immolation have also been recorded by the Jesuit priests of France in the early 17th century. However, their practice of this was not intended to be fatal: they would burn certain parts of their bodies (limbs such as the forearm or the thigh) to symbolise the pain Jesus endured while upon the cross. A 1973 study by a prison doctor suggested that people who choose self-immolation as a form of suicide are more likely to be in a "disturbed state of consciousness", such as epilepsy.

Political protest

As a form of political protest, the 14th Dalai Lama explained in 2013 and 2015 the act of self-immolation:

I think the self-burning itself on practice of non-violence. These people, you see, they [could instead] easily use bomb explosive, more casualty people. But they didn't do that. Only sacrifice their own life. So this also is part of practice of non-violence.

Self-immolations are often public and political statements that are often reported by the news media. They can be seen by others as a type of altruistic suicide for a collective cause, and are not intended to inflict physical harm on others or cause material damage. They attract attention to a specific cause and those who undergo the act may be seen as martyrs. Self-immolation does not guarantee death for the burned; self-immolation survivors suffer from severe disfigurements from resulting burns.

Vietnam

Thích Quảng Đức's self-immolation during the Buddhist crisis

The Buddhist crisis in South Vietnam saw the persecution of the country's majority religion under the administration of Catholic president Ngô Đình Diệm. Several Buddhist monks, including the most famous case of Thích Quảng Đức, immolated themselves in protest.

The example set by self-immolators in the mid 20th century did spark numerous similar acts between 1963 and 1971, most of which occurred in Asia and the United States in conjunction with protests opposing the Vietnam War. Researchers counted almost 100 self-immolations covered by The New York Times and The Times.

Soviet Bloc

In 1968 the practice spread to the Soviet bloc with the self-immolation of Polish accountant and Armia Krajowa veteran Ryszard Siwiec, as well as those of two Czech students, Jan Palach and Jan Zajíc, and of toolmaker Evžen Plocek, in protest against the Warsaw Pact invasion of Czechoslovakia. As a protest against Soviet rule in Lithuania, 19-year-old Romas Kalanta set himself on fire in Kaunas in 1972. In 1978 Ukrainian dissident and former political prisoner Oleksa Hirnyk burnt himself near the tomb of the Ukrainian poet Taras Shevchenko protesting against the russification of Ukraine under Soviet rule. On 2 March 1989, Liviu Cornel Babeș set himself on fire on the Bradu ski slope at Poiana Brașov as a sign of protest against the communist regime. He left the message: „Stop Mörder! Brașov = Auschwitz". He was taken to the Brașov county hospital, where he died two hours later.

Russian Federation

In 2020, the practice resumed when Russian journalist Irina Slavina burned herself in Nizhny Novgorod after her last post on Facebook, in which she wrote: "I ask you to blame the Russian Federation for my death". Also, cases of self-immolation as a form of political protest were recorded in Moscow, St. Petersburg, Ufa, Izhevsk, Kemerovo and other cities of the Russian Federation. Most of the cases were fatal.

India

The practice continues, notably in India: as many as 1,451 and 1,584 self-immolations were reported there in 2000 and 2001, respectively. A particularly high wave of self-immolation in India was recorded in 1990 protesting the Reservation in India. Tamil Nadu has the highest number of self-immolations in India to date.

Iran

In Iran, most self-immolations have been performed by citizens protesting the tempestuous changes brought upon after the Iranian Revolution. Many of these instances have gone largely unreported by regime authority, but have been discussed and documented by established witnesses. Provinces that were involved more intensively in postwar problems feature higher rates of self-immolation. These undocumented demonstrations of protest are deliberated upon worldwide, by professionals such as Iranian historians who appear on international broadcasts such as Voice of America, and use the immolations as propaganda to direct criticism towards the Censorship in Iran. One specifically well documented self-immolation transpired in 1993, 14 years after the revolution, and was performed by Homa Darabi, a self-proclaimed political activist affiliated with the Nation Party of Iran. Darabi is known for her political self-immolation in protest to the compulsory hijab. Self-immolation protests continue to take place against the regime to this day. Most recently accounted for is the September 2019 death of Sahar Khodayari, protesting a possible sentence of six months in prison for having tried to enter a public stadium to watch a football game, against the national ban against women at such events. One month after her death, Iranian women were allowed to attend a football match in Iran for the first time in 40 years.

People's Republic of China

In 2009, the monk Tapey at Kirti Monastery in Amdo self-immolated in protest of the Chinese government's restrictions placed against an important ceremony. A wave of self-immolations began in 2011, after another monk, Phuntsok, also from Kirti Monastery self-immolated. The wave continued until 2019 and resumed again in 2022. As of April 2022, there were 161 confirmed cases in Tibet and 10 others made in solidarity outside of Tibet. With the self-immolations by Tibetans, most of these protests (some 80%) end in death, while eyewitness report state many of the protestors have been shot and beaten while burning, and then arrested by Chinese authorities and disappeared.

The 14th Dalai Lama has spoken with respect and compassion for those who engage in self-immolation, and blamed the self-immolations on "cultural genocide" by the Chinese. The Chinese government claims that he and the exiled Tibetan government are inciting these acts. In 2013, the Dalai Lama questioned the effectiveness of self-immolation as a demonstration tactic. He has also expressed that the Tibetans are acting of their own free will and stated that he cannot influence them to stop carrying out immolation as a form of protest.

Arab Spring

A wave of self-immolation suicides occurred in conjunction with the Arab Spring protests in the Middle East and North Africa, with at least 14 recorded incidents. These suicides assisted in inciting the Arab Spring, including the 2010–2011 Tunisian revolution, the main catalyst of which was the self-immolation of Mohamed Bouazizi, the 2011 Algerian protests (including many self-immolations in Algeria), and the 2011 Egyptian revolution. There have also been suicide protests in Saudi Arabia, Mauritania, and Syria.

Taiwan

On 3 December 2020, a Taiwanese man self-immolated to protest closure of CTi News.

Australia

On 1 January 2022, an Australian man self-immolated to protest the COVID-19 vaccine mandates and vaccine IDs. He was later taken to the hospital.

United States

On 14 April 2018, David Buckel self immolated in Prospect Park in Brooklyn. Shortly before lighting himself on fire he sent an email to several news outlets which included the statement "Most humans on the planet now breathe air made unhealthy by fossil fuels, and many die early deaths as a result—my early death by fossil fuel reflects what we are doing to ourselves."

Wynn Bruce, a climate activist from Boulder, Colorado self-immolated on the steps of the Supreme Court of the United States on Earth Day, 22 April 2022. On 28 March 2022, he made a Facebook post stating “This is not humor. It is all about breathing” followed by “Clean air matters.”

Conway's Game of Life

From Wikipedia, the free encyclopedia

A single Gosper's glider gun creating gliders
 
A screenshot of a puffer-type breeder (red) that leaves glider guns (green) in its wake, which in turn create gliders (blue) (animation)

The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is a zero-player game, meaning that its evolution is determined by its initial state, requiring no further input. One interacts with the Game of Life by creating an initial configuration and observing how it evolves. It is Turing complete and can simulate a universal constructor or any other Turing machine.

Rules

The universe of the Game of Life is an infinite, two-dimensional orthogonal grid of square cells, each of which is in one of two possible states, live or dead (or populated and unpopulated, respectively). Every cell interacts with its eight neighbours, which are the cells that are horizontally, vertically, or diagonally adjacent. At each step in time, the following transitions occur:

  1. Any live cell with fewer than two live neighbours dies, as if by underpopulation.
  2. Any live cell with two or three live neighbours lives on to the next generation.
  3. Any live cell with more than three live neighbours dies, as if by overpopulation.
  4. Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.

These rules, which compare the behavior of the automaton to real life, can be condensed into the following:

  1. Any live cell with two or three live neighbours survives.
  2. Any dead cell with three live neighbours becomes a live cell.
  3. All other live cells die in the next generation. Similarly, all other dead cells stay dead.

The initial pattern constitutes the seed of the system. The first generation is created by applying the above rules simultaneously to every cell in the seed, live or dead; births and deaths occur simultaneously, and the discrete moment at which this happens is sometimes called a tick. Each generation is a pure function of the preceding one. The rules continue to be applied repeatedly to create further generations.

Origins

Stanislaw Ulam, while working at the Los Alamos National Laboratory in the 1940s, studied the growth of crystals, using a simple lattice network as his model. At the same time, John von Neumann, Ulam's colleague at Los Alamos, was working on the problem of self-replicating systems. Von Neumann's initial design was founded upon the notion of one robot building another robot. This design is known as the kinematic model. As he developed this design, von Neumann came to realize the great difficulty of building a self-replicating robot, and of the great cost in providing the robot with a "sea of parts" from which to build its replicant. Neumann wrote a paper entitled "The general and logical theory of automata" for the Hixon Symposium in 1948. Ulam was the one who suggested using a discrete system for creating a reductionist model of self-replication. Ulam and von Neumann created a method for calculating liquid motion in the late 1950s. The driving concept of the method was to consider a liquid as a group of discrete units and calculate the motion of each based on its neighbors' behaviors. Thus was born the first system of cellular automata. Like Ulam's lattice network, von Neumann's cellular automata are two-dimensional, with his self-replicator implemented algorithmically. The result was a universal copier and constructor working within a cellular automaton with a small neighborhood (only those cells that touch are neighbors; for von Neumann's cellular automata, only orthogonal cells), and with 29 states per cell. Von Neumann gave an existence proof that a particular pattern would make endless copies of itself within the given cellular universe by designing a 200,000 cell configuration that could do so. This design is known as the tessellation model, and is called a von Neumann universal constructor.

Motivated by questions in mathematical logic and in part by work on simulation games by Ulam, among others, John Conway began doing experiments in 1968 with a variety of different two-dimensional cellular automaton rules. Conway's initial goal was to define an interesting and unpredictable cellular automaton. According to Martin Gardner, Conway experimented with different rules, aiming for rules that would allow for patterns to "apparently" grow without limit, while keeping it difficult to prove that any given pattern would do so. Moreover, some "simple initial patterns" should "grow and change for a considerable period of time" before settling into a static configuration or a repeating loop. Conway later wrote that the basic motivation for Life was to create a "universal" cellular automaton.

The game made its first public appearance in the October 1970 issue of Scientific American, in Martin Gardner's "Mathematical Games" column, which was based on personal conversations with Conway. Theoretically, the Game of Life has the power of a universal Turing machine: anything that can be computed algorithmically can be computed within the Game of Life. Gardner wrote, "Because of Life's analogies with the rise, fall and alterations of a society of living organisms, it belongs to a growing class of what are called 'simulation games' (games that resemble real-life processes)."

Since its publication, the Game of Life has attracted much interest because of the surprising ways in which the patterns can evolve. It provides an example of emergence and self-organization. A version of Life that incorporates random fluctuations has been used in physics to study phase transitions and nonequilibrium dynamics. The game can also serve as a didactic analogy, used to convey the somewhat counter-intuitive notion that design and organization can spontaneously emerge in the absence of a designer. For example, philosopher Daniel Dennett has used the analogy of the Game of Life "universe" extensively to illustrate the possible evolution of complex philosophical constructs, such as consciousness and free will, from the relatively simple set of deterministic physical laws which might govern our universe.

The popularity of the Game of Life was helped by its coming into being at the same time as increasingly inexpensive computer access. The game could be run for hours on these machines, which would otherwise have remained unused at night. In this respect, it foreshadowed the later popularity of computer-generated fractals. For many, the Game of Life was simply a programming challenge: a fun way to use otherwise wasted CPU cycles. For some, however, the Game of Life had more philosophical connotations. It developed a cult following through the 1970s and beyond; current developments have gone so far as to create theoretic emulations of computer systems within the confines of a Game of Life board.

Examples of patterns

Many different types of patterns occur in the Game of Life, which are classified according to their behaviour. Common pattern types include: still lifes, which do not change from one generation to the next; oscillators, which return to their initial state after a finite number of generations; and spaceships, which translate themselves across the grid.

The earliest interesting patterns in the Game of Life were discovered without the use of computers. The simplest still lifes and oscillators were discovered while tracking the fates of various small starting configurations using graph paper, blackboards, and physical game boards, such as those used in Go. During this early research, Conway discovered that the R-pentomino failed to stabilize in a small number of generations. In fact, it takes 1103 generations to stabilize, by which time it has a population of 116 and has generated six escaping gliders; these were the first spaceships ever discovered.

Frequently occurring examples (in that they emerge frequently from a random starting configuration of cells) of the three aforementioned pattern types are shown below, with live cells shown in black and dead cells in white. Period refers to the number of ticks a pattern must iterate through before returning to its initial configuration.

The pulsar is the most common period-3 oscillator. The great majority of naturally occurring oscillators have a period of 2, like the blinker and the toad, but oscillators of many periods are known to exist, and oscillators of periods 4, 8, 14, 15, 30, and a few others have been seen to arise from random initial conditions. Patterns which evolve for long periods before stabilizing are called Methuselahs, the first-discovered of which was the R-pentomino. Diehard is a pattern that eventually disappears, rather than stabilizing, after 130 generations, which is conjectured to be maximal for patterns with seven or fewer cells. Acorn takes 5206 generations to generate 633 cells, including 13 escaped gliders.

The R-pentomino
Diehard
Acorn

Conway originally conjectured that no pattern can grow indefinitely—i.e. that for any initial configuration with a finite number of living cells, the population cannot grow beyond some finite upper limit. In the game's original appearance in "Mathematical Games", Conway offered a prize of fifty dollars to the first person who could prove or disprove the conjecture before the end of 1970. The prize was won in November by a team from the Massachusetts Institute of Technology, led by Bill Gosper; the "Gosper glider gun" produces its first glider on the 15th generation, and another glider every 30th generation from then on. For many years, this glider gun was the smallest one known. In 2015, a gun called the "Simkin glider gun", which releases a glider every 120th generation, was discovered that has fewer live cells but which is spread out across a larger bounding box at its extremities.

Gosper glider gun
 
Simkin glider gun

Smaller patterns were later found that also exhibit infinite growth. All three of the patterns shown below grow indefinitely. The first two create a single block-laying switch engine: a configuration that leaves behind two-by-two still life blocks as it translates itself across the game's universe. The third configuration creates two such patterns. The first has only ten live cells, which has been proven to be minimal. The second fits in a five-by-five square, and the third is only one cell high.

Game of life infinite1.svg     Game of life infinite2.svg

Game of life infinite3.svg

Later discoveries included other guns, which are stationary, and which produce gliders or other spaceships; puffer trains, which move along leaving behind a trail of debris; and rakes, which move and emit spaceships. Gosper also constructed the first pattern with an asymptotically optimal quadratic growth rate, called a breeder or lobster, which worked by leaving behind a trail of guns.

It is possible for gliders to interact with other objects in interesting ways. For example, if two gliders are shot at a block in a specific position, the block will move closer to the source of the gliders. If three gliders are shot in just the right way, the block will move farther away. This sliding block memory can be used to simulate a counter. It is possible to construct logic gates such as AND, OR, and NOT using gliders. It is possible to build a pattern that acts like a finite-state machine connected to two counters. This has the same computational power as a universal Turing machine, so the Game of Life is theoretically as powerful as any computer with unlimited memory and no time constraints; it is Turing complete. In fact, several different programmable computer architectures have been implemented in the Game of Life, including a pattern that simulates Tetris.

Furthermore, a pattern can contain a collection of guns that fire gliders in such a way as to construct new objects, including copies of the original pattern. A universal constructor can be built which contains a Turing complete computer, and which can build many types of complex objects, including more copies of itself.

In 2018, the first truly elementary knightship, Sir Robin, was discovered by Adam P. Goucher. A knightship is a spaceship that moves two squares left for every one square it moves down (like a knight in chess), as opposed to moving orthogonally or along a 45° diagonal. This is the first new spaceship movement pattern for an elementary spaceship found in forty-eight years. "Elementary" means that it cannot be decomposed into smaller interacting patterns such as gliders and still lifes.

Undecidability

Many patterns in the Game of Life eventually become a combination of still lifes, oscillators, and spaceships; other patterns may be called chaotic. A pattern may stay chaotic for a very long time until it eventually settles to such a combination.

The Game of Life is undecidable, which means that given an initial pattern and a later pattern, no algorithm exists that can tell whether the later pattern is ever going to appear. This is a corollary of the halting problem: the problem of determining whether a given program will finish running or continue to run forever from an initial input.

Indeed, since the Game of Life includes a pattern that is equivalent to a universal Turing machine (UTM), this deciding algorithm, if it existed, could be used to solve the halting problem by taking the initial pattern as the one corresponding to a UTM plus an input, and the later pattern as the one corresponding to a halting state of the UTM. It also follows that some patterns exist that remain chaotic forever. If this were not the case, one could progress the game sequentially until a non-chaotic pattern emerged, then compute whether a later pattern was going to appear.

Self-replication

On May 18, 2010, Andrew J. Wade announced a self-constructing pattern, dubbed "Gemini", that creates a copy of itself while destroying its parent. This pattern replicates in 34 million generations, and uses an instruction tape made of gliders oscillating between two stable configurations made of Chapman–Greene construction arms. These, in turn, create new copies of the pattern, and destroy the previous copy. Gemini is also a spaceship, and is the first spaceship constructed in the Game of Life that is an oblique spaceship, which is a spaceship that is neither orthogonal nor purely diagonal. In December 2015, diagonal versions of the Gemini were built.

On November 23, 2013, Dave Greene built the first replicator in the Game of Life that creates a complete copy of itself, including the instruction tape.

In October 2018, Adam P. Goucher finished his construction of the 0E0P metacell, a metacell capable of self-replication. This differed from previous metacells, such as the OTCA metapixel by Brice Due, which only worked with already constructed copies near them. The 0E0P metacell works by using construction arms to create copies that simulate the programmed rule. The actual simulation of the Game of Life or other Moore neighbourhood rules is done by simulating an equivalent rule using the von Neumann neighbourhood with more states. The name 0E0P is short for "Zero Encoded by Zero Population", which indicates that instead of a metacell being in an "off" state simulating empty space, the 0E0P metacell removes itself when the cell enters that state, leaving a blank space.

Iteration

From most random initial patterns of living cells on the grid, observers will find the population constantly changing as the generations tick by. The patterns that emerge from the simple rules may be considered a form of mathematical beauty. Small isolated subpatterns with no initial symmetry tend to become symmetrical. Once this happens, the symmetry may increase in richness, but it cannot be lost unless a nearby subpattern comes close enough to disturb it. In a very few cases, the society eventually dies out, with all living cells vanishing, though this may not happen for a great many generations. Most initial patterns eventually burn out, producing either stable figures or patterns that oscillate forever between two or more states; many also produce one or more gliders or spaceships that travel indefinitely away from the initial location. Because of the nearest-neighbour based rules, no information can travel through the grid at a greater rate than one cell per unit time, so this velocity is said to be the cellular automaton speed of light and denoted c.

Algorithms

Early patterns with unknown futures, such as the R-pentomino, led computer programmers to write programs to track the evolution of patterns in the Game of Life. Most of the early algorithms were similar: they represented the patterns as two-dimensional arrays in computer memory. Typically, two arrays are used: one to hold the current generation, and one to calculate its successor. Often 0 and 1 represent dead and live cells, respectively. A nested for loop considers each element of the current array in turn, counting the live neighbours of each cell to decide whether the corresponding element of the successor array should be 0 or 1. The successor array is displayed. For the next iteration, the arrays may swap roles so that the successor array in the last iteration becomes the current array in the next iteration, or one may copy the values of the second array into the first array then update the second array from the first array again.

A variety of minor enhancements to this basic scheme are possible, and there are many ways to save unnecessary computation. A cell that did not change at the last time step, and none of whose neighbours changed, is guaranteed not to change at the current time step as well, so a program that keeps track of which areas are active can save time by not updating inactive zones.

Game of Life on the surface of a trefoil knot
The Game of Life on the surface of a trefoil knot

To avoid decisions and branches in the counting loop, the rules can be rearranged from an egocentric approach of the inner field regarding its neighbours to a scientific observer's viewpoint: if the sum of all nine fields in a given neighbourhood is three, the inner field state for the next generation will be life; if the all-field sum is four, the inner field retains its current state; and every other sum sets the inner field to death.

To save memory, the storage can be reduced to one array plus two line buffers. One line buffer is used to calculate the successor state for a line, then the second line buffer is used to calculate the successor state for the next line. The first buffer is then written to its line and freed to hold the successor state for the third line. If a toroidal array is used, a third buffer is needed so that the original state of the first line in the array can be saved until the last line is computed.

Glider gun within a toroidal array. The stream of gliders eventually wraps around and destroys the gun.
 
Red glider on the square lattice with periodic boundary conditions

In principle, the Game of Life field is infinite, but computers have finite memory. This leads to problems when the active area encroaches on the border of the array. Programmers have used several strategies to address these problems. The simplest strategy is to assume that every cell outside the array is dead. This is easy to program but leads to inaccurate results when the active area crosses the boundary. A more sophisticated trick is to consider the left and right edges of the field to be stitched together, and the top and bottom edges also, yielding a toroidal array. The result is that active areas that move across a field edge reappear at the opposite edge. Inaccuracy can still result if the pattern grows too large, but there are no pathological edge effects. Techniques of dynamic storage allocation may also be used, creating ever-larger arrays to hold growing patterns. The Game of Life on a finite field is sometimes explicitly studied; some implementations, such as Golly, support a choice of the standard infinite field, a field infinite only in one dimension, or a finite field, with a choice of topologies such as a cylinder, a torus, or a Möbius strip.

Alternatively, programmers may abandon the notion of representing the Game of Life field with a two-dimensional array, and use a different data structure, such as a vector of coordinate pairs representing live cells. This allows the pattern to move about the field unhindered, as long as the population does not exceed the size of the live-coordinate array. The drawback is that counting live neighbours becomes a hash-table lookup or search operation, slowing down simulation speed. With more sophisticated data structures this problem can also be largely solved.

For exploring large patterns at great time depths, sophisticated algorithms such as Hashlife may be useful. There is also a method for implementation of the Game of Life and other cellular automata using arbitrary asynchronous updates whilst still exactly emulating the behaviour of the synchronous game. Source code examples that implement the basic Game of Life scenario in various programming languages, including C, C++, Java and Python can be found at Rosetta Code.

Variations

Since the Game of Life's inception, new, similar cellular automata have been developed. The standard Game of Life is symbolized as B3/S23. A cell is born if it has exactly three neighbours, survives if it has two or three living neighbours, and dies otherwise. The first number, or list of numbers, is what is required for a dead cell to be born. The second set is the requirement for a live cell to survive to the next generation. Hence B6/S16 means "a cell is born if there are six neighbours, and lives on if there are either one or six neighbours". Cellular automata on a two-dimensional grid that can be described in this way are known as Life-like cellular automata. Another common Life-like automaton, Highlife, is described by the rule B36/S23, because having six neighbours, in addition to the original game's B3/S23 rule, causes a birth. HighLife is best known for its frequently occurring replicators.

Additional Life-like cellular automata exist. The vast majority of these 218 different rules produce universes that are either too chaotic or too desolate to be of interest, but a large subset do display interesting behavior. A further generalization produces the isotropic rulespace, with 2102 possible cellular automaton rules (the Game of Life again being one of them). These are rules that use the same square grid as the Life-like rules and the same eight-cell neighbourhood, and are likewise invariant under rotation and reflection. However, in isotropic rules, the positions of neighbour cells relative to each other may be taken into account in determining a cell's future state—not just the total number of those neighbours.

A sample of a 48-step oscillator along with a 2-step oscillator and a 4-step oscillator from a two-dimensional hexagonal Game of Life (rule H:B2/S34)

Some variations on the Game of Life modify the geometry of the universe as well as the rule. The above variations can be thought of as a two-dimensional square, because the world is two-dimensional and laid out in a square grid. One-dimensional square variations, known as elementary cellular automata, and three-dimensional square variations have been developed, as have two-dimensional hexagonal and triangular variations. A variant using aperiodic tiling grids has also been made.

Conway's rules may also be generalized such that instead of two states, live and dead, there are three or more. State transitions are then determined either by a weighting system or by a table specifying separate transition rules for each state; for example, Mirek's Cellebration's multi-coloured Rules Table and Weighted Life rule families each include sample rules equivalent to the Game of Life.

Patterns relating to fractals and fractal systems may also be observed in certain Life-like variations. For example, the automaton B1/S12 generates four very close approximations to the Sierpinski triangle when applied to a single live cell. The Sierpinski triangle can also be observed in the Game of Life by examining the long-term growth of an infinitely long single-cell-thick line of live cells, as well as in Highlife, Seeds (B2/S), and Wolfram's Rule 90.

Immigration is a variation that is very similar to the Game of Life, except that there are two on states, often expressed as two different colours. Whenever a new cell is born, it takes on the on state that is the majority in the three cells that gave it birth. This feature can be used to examine interactions between spaceships and other objects within the game. Another similar variation, called QuadLife, involves four different on states. When a new cell is born from three different on neighbours, it takes the fourth value, and otherwise, like Immigration, it takes the majority value. Except for the variation among on cells, both of these variations act identically to the Game of Life.

Music

Various musical composition techniques use the Game of Life, especially in MIDI sequencing. A variety of programs exist for creating sound from patterns generated in the Game of Life.

Notable programs

The 6366548773467669985195496000th (6×1027) generation of a Turing machine, made in the game of Life, computed in less than 30 seconds on an Intel Core Duo 2 GHz CPU using Golly in Hashlife mode

Computers have been used to follow Game of Life configurations since it was first publicized. When John Conway was first investigating how various starting configurations developed, he tracked them by hand using a go board with its black and white stones. This was tedious and prone to errors. The first interactive Game of Life program was written in an early version of ALGOL 68C for the PDP-7 by M. J. T. Guy and S. R. Bourne. The results were published in the October 1970 issue of Scientific American, along with the statement: "Without its help, some discoveries about the game would have been difficult to make."

A color version of the Game of Life was written by Ed Hall in 1976 for Cromemco microcomputers, and a display from that program filled the cover of the June 1976 issue of Byte. The advent of microcomputer-based color graphics from Cromemco has been credited with a revival of interest in the game.

Two early implementations of the Game of Life on home computers were by Malcolm Banthorpe written in BBC BASIC. The first was in the January 1984 issue of Acorn User magazine, and Banthorpe followed this with a three-dimensional version in the May 1984 issue. Susan Stepney, Professor of Computer Science at the University of York, followed this up in 1988 with Life on the Line, a program that generated one-dimensional cellular automata.

There are now thousands of Game of Life programs online, so a full list will not be provided here. The following is a small selection of programs with some special claim to notability, such as popularity or unusual features. Most of these programs incorporate a graphical user interface for pattern editing and simulation, the capability for simulating multiple rules including the Game of Life, and a large library of interesting patterns in the Game of Life and other cellular automaton rules.

  • Golly is a cross-platform (Windows, Macintosh, Linux, iOS, and Android) open-source simulation system for the Game of Life and other cellular automata (including all Life-like cellular automata, the Generations family of cellular automata from Mirek's Cellebration, and John von Neumann's 29-state cellular automaton) by Andrew Trevorrow and Tomas Rokicki. It includes the Hashlife algorithm for extremely fast generation, and Lua or Python scriptability for both editing and simulation.
  • Mirek's Cellebration is a freeware one- and two-dimensional cellular automata viewer, explorer, and editor for Windows. It includes powerful facilities for simulating and viewing a wide variety of cellular automaton rules, including the Game of Life, and a scriptable editor.
  • Xlife is a cellular-automaton laboratory by Jon Bennett. The standard UNIX X11 Game of Life simulation application for a long time, it has also been ported to Windows. It can handle cellular automaton rules with the same neighbourhood as the Game of Life, and up to eight possible states per cell.
  • Dr. Blob's Organism is a Shoot 'em up based on Conway's Life. In the game, Life continually generates on a group of cells within a "petri dish". The patterns formed are smoothed and rounded to look like a growing amoeba spewing smaller ones (actually gliders). Special "probes" zap the "blob" to keep it from overflowing the dish while destroying its nucleus.

Google implemented an easter egg of the Game of Life in 2012. Users who search for the term are shown an implementation of the game in the search results page.

Why I Am Pro-Abortion, Not Just Pro-Choice

Valerie Tarico

Original Link:  https://secularhumanism.org/2016/07/cont-why-i-am-pro-abortion-not-just-pro-choice/?fbclid=IwAR1uk1ixZh7ObRBXs0ObDkt2TnEoAJ_LhrTEMcQIEsSEIo4uI8HDaNIKR98

I believe that abortion care is a positive social good—and I think it’s time people said so.

Not long ago, the Daily Kos published an article titled “I Am Pro-Choice, Not Pro-Abortion.” “Has anyone ever truly been pro-abortion?” one commenter asked.

Uh. Yes. Me. That would be me.

I am pro-abortion like I’m pro–knee replacement and pro-chemotherapy and pro–cataract surgery. As the last protection against ill-conceived childbearing when all else fails, abortion is part of a set of tools that help women and men to form the families of their choosing. I believe that abortion care is a positive social good. And I suspect that a lot of other people secretly believe the same thing. I think it’s time we said so.

Note: I’m also pro-choice. Choice is about who gets to make the decision. The question of whether and when we bring a new life into the world is, to my mind, one of the most important decisions a person can make. It is too big a decision for us to make for each other, especially for perfect strangers.

But independent of who owns the decision, I’m pro on the procedure. I’ve decided that it’s time, for once and for all, to count it out on my ten fingers.

  1. I’m pro-abortion because being able to delay and limit childbearing is fundamental to female empowerment and equality. A woman who lacks the means to manage her fertility lacks the means to manage her life. Any plans, dreams, aspirations, responsibilities or commitments—no matter how important—have a great big contingency clause built-in: “… until or unless I get pregnant, in which case all bets are off.” Think of any professional woman you know. She wouldn’t be in that role if she hadn’t been able to time and limit her childbearing. Think of any girl you know who imagines becoming a professional woman. She won’t get there unless she has effective, reliable means to manage her fertility. In generations past, nursing care was provided by nuns and teachers who were spinsters, because avoiding sexual intimacy was the only way women could avoid unpredictable childbearing and so be freed up to serve their communities in other capacities. But if you think that abstinence should be our model for modern fertility management, consider the little graves that get found every so often under old nunneries and Catholic homes for unwed mothers.
  2. I’m pro-abortion because well-timed pregnancies give children a healthier start in life. We now have ample evidence that babies do best when women are able to space their pregnancies and get both prenatal and preconception care. The specific nutrients we ingest in the weeks before we get pregnant can have a lifelong effect on the well-being of our offspring. Rapid repeat pregnancies increase the risk of low birth-weight babies and other complications. Wanted babies are more likely to get their toes kissed, to be welcomed into families that are financially and emotionally ready to receive them, to get preventive medical care during childhood, and to receive the kinds of loving engagement that helps young brains to develop.
  3. I’m pro-abortion because I take motherhood seriously. Most female bodies can incubate a baby; thanks to antibiotics, cesareans, and anti-hemorrhage drugs, most of us are able to survive pushing a baby out into the world. But parenting is a lot of work, and doing it well takes twenty dedicated years of focus, attention, patience, persistence, social support, mental health, money, and a whole lot more. This is the biggest, most life-transforming thing most of us will ever do. The idea that women should simply go with it when they find themselves pregnant after a one-night stand, or a rape, or a broken condom completely trivializes motherhood.
  4. I’m pro-abortion because intentional childbearing helps couples, families, and communities to get out of poverty. Decades of research in countries ranging from the United States to Bangladesh show that reproductive policy is economic policy. It is no coincidence that the American middle class rose along with the ability of couples to plan their families, starting at the beginning of the last century. Having two or three kids instead of eight or ten was critical to prospering in the modern industrial economy. Early, unsought childbearing nukes economic opportunity and contributes to multigenerational poverty. Today in the United States, unsought pregnancy and childbearing is declining for everyone but the poorest families and communities, contributing to what some call a growing “caste system” in America. Strong, determined girls and women sometimes beat the odds, but their stories inspire us precisely because they are the exceptions to the rule. Justice dictates that the full range of fertility management tools—including the best state-of-the-art contraceptive technologies and, when that fails, abortion care—be equally available to all, not just a privileged few.
  5. I’m pro-abortion because reproduction is a highly imperfect process. Genetic recombination is a complicated progression with flaws and false starts at every step along the way. To compensate, in every known species including humans, reproduction operates as a big funnel. Many more eggs and sperm are produced than will ever meet; more combine into embryos than will ever implant; more implant than will grow into babies; and more babies are born than will grow up to have babies of their own. This systematic culling makes God or nature the world’s biggest abortion provider: nature’s way of producing healthy kids essentially requires every woman to have an abortion mill built into her own body. In humans, an estimated 60 to 80 percent of fertilized eggs self-destruct before becoming babies, which is why the people who kill the most embryos are those like the Duggars who try to maximize their number of pregnancies. But the weeding-out process is also highly imperfect. Sometimes perfectly viable combinations boot themselves out; sometimes horrible defects slip through. A woman’s body may be less fertile when she is stressed or ill or malnourished, but as pictures of skeletal moms and babies show, some women conceive even under devastating circumstances. Like any other medical procedure, therapeutic contraception and abortion complement natural processes designed to help us survive and thrive.
  6. I’m pro-abortion because I think morality is about the well-being of sentient beings. I believe that morality is about the lived experience of sentient beings—beings who can feel pleasure and pain, preference and intention and who at their most complex can live in relation to other beings, love and be loved, and value their own existence. What are they capable of wanting? What are they capable of feeling? These are the questions my husband and I explored with our children when they were figuring out their responsibility to their chickens and guinea pigs. It was a lesson that turned expensive when the girls stopped drinking milk from cows that didn’t get to see the light of day or eat grass, but it’s not one I regret. Do unto others as they want you to do unto them. It’s called the “Platinum Rule.” In this moral universe, real people count more than potential people, hypothetical people, or corporate people.
  7. I’m pro-abortion because contraceptives are imperfect, and people are too. The pill is 1960s technology, now half a century old. For decades, women were told that the pill was 99 percent effective, and they blamed themselves when they got pregnant anyway. But that 99 percent is a “perfect use” statistic. In the real world, where most of us live, people aren’t perfect. In the real world, one in eleven women relying on the pill gets pregnant each year. For a couple relying on condoms, that’s one in six. Young and poor women—those whose lives are least predictable and most vulnerable to being thrown off course—are also those who have the most difficulty taking pills consistently. Pill technology most fails those who need it most, which makes abortion access a matter not only of compassion but of justice. State-of-the-art IUDs and implants radically change this equation, largely because they take human error out of the picture for years on end, or until a woman wants a baby. And despite the deliberate misinformation being spread by opponents, these methods are genuine contraceptives, not abortifacients. Depending on the method chosen, they disable sperm or block their path, or prevent an egg from being released. Once settled into place, an IUD or implant drops the annual pregnancy rate below one in five hundred. And guess what? Teen pregnancies and abortions plummet—which makes me happy, because even though I’m pro-abortion, I’d love the need for abortion to go away. Why mitigate harm when you can prevent it?
  8. I’m pro-abortion because I believe in mercy, grace, compassion, and the power of fresh starts. Many years ago, my friend Chip was driving his family on vacation when his kids started squabbling. His wife, Marla, undid her seatbelt to help them, and, as Chip looked over at her, their top-heavy minivan veered onto the shoulder and then rolled, and Marla died. Sometimes people make mistakes or have accidents that they pay for the rest of their lives. But I myself have swerved onto the shoulder and simply swerved back. The price we pay for a lapse in attention or judgment or an accident of any kind isn’t proportional to the error we made. Who among us hasn’t had unprotected sex when the time or situation or partnership wasn’t quite right for bringing a new life into the world? Most of the time we get lucky; sometimes we don’t. And in those situations we rely on the mercy, compassion, and generosity of others. In this regard, an unsought pregnancy is like any other accident. I can walk today only because surgeons reassembled my lower leg after it was crushed between the front of a car and a bicycle frame when I was a teen. And I can walk today (and run and jump) because another team of surgeons reassembled my knee joint after I fell off a ladder. And I can walk today (and bicycle with my family) because a third team of surgeons repaired my other knee after I pulled a whirring brush mower onto myself, cutting clear through bone. Three accidents, all my own doing, and three knee surgeries. Some women have three abortions.
  9. I’m pro-abortion because the future is always in motion, and we have the power and responsibility to shape it well. As a college student, I read a Ray Bradbury story about a man who travels back into prehistory on a “time safari.” The tourists have been coached about the importance of not disturbing anything lest they change the flow of history. When they return to the present, they realize that the outcome of an election has changed, and they discover that the protagonist, who had gone off the trail, has a crushed butterfly on the bottom of his shoe. In baby-making, as in Bradbury’s story, the future is always in motion, and every little thing we do has consequences we have no way to predict. Any small change means that a different child comes into the world. Which nights your mother had headaches, the sexual position of your parents when they conceived you, whether or not your mother rolled over in bed afterward—if any of these things had been different, someone else would be here instead of you. Every day, men and women make small choices and potential people wink into and out of existence. We move, and our movements ripple through time in ways that are incomprehensible, and we can never know what the alternate futures might have been. But some things we can know or predict, at least at the level of probability, and I think this knowledge provides a basis for guiding wise reproductive decisions. My friend Judy says that parenting begins before conception. I agree. How and when we choose to carry forward a new life can stack the odds in favor of our children or against them, and to me that is a sacred trust.
  10. I’m pro-abortion because I love my daughter. I first wrote the story of my own abortion when Dr. George Tiller was murdered, and I couldn’t bear the thought of abortion providers standing in the crosshairs alone. “My Abortion Baby” was about my daughter, Brynn, who exists only because a kind doctor such as George Tiller gave me and my husband the gift of a fresh start when we learned that our wanted pregnancy was unhealthy. Brynn literally embodies the ever-changing flow of the future, because she could not exist in an alternate universe in which I would have carried that first pregnancy to term. She was conceived while I would still have been pregnant with a child we had begun to imagine but who never came to be. My husband and I felt very clear that carrying forward that pregnancy would have been a violation of our values, and neither of us ever second-guessed our decision. Even so, I grieved. Even when I got pregnant again a few months later, I remember feeling petulant and thinking, I want that baby, not this one. And then Brynn came out into the world, and I looked into her eyes, fell in love, and never looked back.

All around us living, breathing, and loving are the chosen children of mothers who waited, who ended an ill-timed or unhealthy pregnancy and then later chose to carry forward a new life. “I was only going to have two children,” my friend Jane said as her daughters raced, screeching joyfully, across my lawn. Jane followed them with her eyes. “My abortions let me have these two when the time was right, with someone I loved.”

Those who see abortion as an unmitigated evil often talk about the “millions of missing people” who were not born into this world because a pregnant woman decided “Not now.” But they never talk about the millions of children and adults who are here today only because their mothers had abortions—real people who exist in this version of the future, people who are living out their lives all around us—loving, laughing, suffering, struggling, dancing, dreaming, and having babies of their own.

When those who oppose abortion lament the “missing people,” I hear an echo of my own petulant thought: I want that person, not this one. And I wish that they could simply experience what I did, that they could look into the beautiful eyes of the people in front of them and fall in love.

Computational complexity theory

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Computational_complexity_theory ...