Can we tell a machine that looks like a person from a real one? Is thinking just calculation? A question more than 300 years old travels through gears, cards and switches, and arrives at the question of 1950,
011637 · Telling apart
Telling a machine from a person
If a machine moved just like a person, could we tell it apart from one?
In 1637, in Part 5 of the (Discours de la methode), Descartes wrote that even if there were machines built to look like a human body and imitate its actions, there would be (translated) of recognizing that they were not real human beings.
The first is language. Descartes admitted that a machine could be made that, touched in one spot, asks (translated), and touched in another, cries out (translated). But such a machine could not arrange words in many different ways (translated). The second is the breadth of situations it can handle. A machine needs a special arrangement of parts for each action, so it falls short of reason, which he called (translated) that works in any situation.
The figure on the right is a table machine that returns a fixed word to a fixed stimulus. It cannot answer a question that is not in its table. Even if you make the table bigger, the number of sentences you can build from words grows much faster than the table does.
number of arrangements=VL
V
number of words available
L
length of the sentence (in words)
More than a story about machines
Right after this, in the same paragraph, Descartes uses the same two tests to separate humans from animals, and goes on to claim that animals have no reason at all. It was less a prediction about machines than part of an argument for the special place of human reason.
About 300 years later, in 1950, Turing came up with the , which tells a machine apart through an exchange of words (spread 18 of this chapter). In 2025, an experiment was published in which an AI that writes text (a large language model) was judged to be human in a high share of five-minute conversations. Opinions are divided on whether this counts as passing Descartes' first test.
Sources & confidence (1)Telling a machine from a person
1637Verified in the original
Descartes, (1637): (translated) of telling a human-like machine from a human
In Part 5 of “Discours de la methode”, René Descartes starts from automata made by human hands (moving machines) and argues that animal bodies, too, are like machines made by God. He then writes that even if a machine looked like a human body and imitated its movements, there are (translated) of telling it is not a real human. (1) A machine can never put words or signs together and answer according to the meaning of what is said in front of it, something even the dullest person can do. (2) Even if a machine does many things as well as a human or better, it will certainly fail at something else. Reason is a universal instrument that can be used in every situation, but a machine needs a particular arrangement of parts for each action, so it is practically impossible to fit into one machine enough arrangements to cover every situation in life. It can be read as an idea that came about 300 years before Turing’s (1950).
What happened next:On (1): in March 2025, researchers at a US university (UC San Diego) ran an experiment in which an interrogator chatted for 5 minutes with a human and a machine at the same time. They reported in a paper (arXiv) that a large language AI (GPT-4.5), told to play the part of a human, was judged to be the human 73% of the time (the announcement of one research group). Whether this counts as what Descartes called (translated) is a matter of differing views. On (2): whether a machine that can act like a human in any situation in life (in today’s words, artificial general intelligence) has been built is still disputed in 2026 (see the records of the fourth boom’s predictions).
What we still don’t know:Whether a machine could have (translated) of reason mentioned in (2), and whether passing test (1) would mean the machine understands meaning, are still unsettled today. (In 1950 Turing himself replaced the question with a different question. See record → Turing publishes a paper discussing mac….)
What the figure shows:A machine that gives fixed replies to fixed prompts from a table cannot answer questions outside that table. Enlarging the table cannot keep up, because the number of sentences made by combining words grows much faster.
Sentence length and the share the table covers (the vertical axis goes up in steps of 10 times)
This is the same mechanism as "Try it", written as Python code. Press ▶ Run and the result appears below. Change the numbers and run it again.
u02_descartes_table.py
021651 · Thinking = calculating
Is thinking just adding and subtracting?
Can careful reasoning be written down as a calculation?
In 1651, in Chapter 5 of , , Hobbes wrote: . What is added is not numbers but names (words) that people have agreed on. Logicians, he wrote, add names to make statements, and add statements to make syllogisms. Just as people make mistakes in arithmetic, he said, even careful people make mistakes in reasoning.
The figure on the right draws names as circles (sets). The statement "all humans are animals" means emptying the part of the human circle that lies outside the animal circle. Cross out regions using the two premises, and you can read the conclusion from the regions that are left. If you check every case of crossing out and keeping, you can check mechanically whether an argument is valid.
In the introduction, he asks whether an automaton driven by springs and wheels might also be said to have , and goes on to say that human art creates even .
premise 1+premise 2 → conclusion (always true if it holds in every world where the premises are true)
world
which of the 8 regions made by 3 circles contain an element (2⁸=256 combinations)
What you think you knowThe popular story:Hobbes was the ancestor of AI and said thinking machines could be built The original source says:In the introduction, is a metaphor for the state (the Leviathan). But Chapter 5 does define thinking itself as a calculation with words, so an idea that leads toward later AI is plainly there.
The patriarch of AI?
Nilsson (2010), who wrote a book on the history of AI, notes that the historian of science Dyson calls Hobbes the .
Sources & confidence (1)Is thinking just adding and subtracting?
1651Verified in the original
Hobbes, (1651):
In his book , Chapter 5, , Thomas Hobbes wrote that to reason (to think in a logical sequence) is nothing but adding parts to get a sum, or subtracting one sum from another to get the remainder. He then defined reason as the chain of agreed general names (words), in other words as nothing more than adding and subtracting. He also wrote that logicians add names together to make statements, and add statements together to make syllogisms. And just as people make mistakes in arithmetic, he said, even the most careful people can make mistakes in reasoning. In the Introduction he asks whether a machine that moves by itself with springs and wheels (an automaton) might not be said to have . He asks whether the heart is not a spring, the nerves strings and the joints wheels, and then goes on to say that human art goes further still and makes , which is the commonwealth (the Leviathan).
The popular story:Hobbes is sometimes presented as an ancestor of AI who said that an artificial human (a thinking machine) could be built (Nilsson writes that Dyson calls Hobbes the ) The original source says:The reference to in the Introduction is a metaphor for the state (the commonwealth), and the talk of automata is only a lead-in to it. But in Chapter 5 he does define thinking (reasoning) itself as a calculation, adding and subtracting, on the chain of general names (words). The idea that thinking is computation, which later led to AI, is clearly written there.
What the figure shows:A statement such as “All humans are animals” removes a region from a circle diagram. Removing regions according to the premises lets a machine check whether a conclusion is valid.
This is the same mechanism as "Try it", written as Python code. Press ▶ Run and the result appears below. Change the numbers and run it again.
u02_syllogism.py
031662–1796 · Japan · Karakuri
The doll that walks with a teacup
How far can a doll go in making fixed movements with only gears and a spring?
In Edo-period Japan, karakuri (mechanical puppets) were a popular show. Around 1662, the first Takeda Omi started a theater devoted to karakuri in Dotonbori, Osaka, called “Takeda’s Theater”, which lasted about 100 years (some books give 1664 as the start).
In 1796, Hosokawa Hanzo Yorinao of Tosa explained, in the (Kikō Zui), with illustrations, the inner workings of 9 kinds of karakuri, including Japanese clocks and tea-serving dolls. The tea-serving doll moves forward when a teacup is set on the tray in its hands, stops when the cup is removed, and turns around and comes back when the cup is set on again. Its power comes from a spring (made of whalebone). The pictures show gears labeled "first wheel" and "second wheel".
In the figure on the right, set the cup on and take it off. The direction, whether it is moving, and whether a cup is present settle the next movement to exactly one choice, and in the same situation it always does the same thing.
next move=table(current state, cup present or absent)
state
a combination of direction (going or returning) and moving or stopped
The figure is a table of the order of movements, not a copy of the gears in the book. Tea-serving dolls themselves existed before the book, and appear in a haiku by Ihara Saikaku.
Sources & confidence (2)The doll that walks with a teacup
1796Verified in the originalSources disagreeJapan
Hosokawa Hanzo Yorinao publishes , a book that explains with diagrams how to make mechanical puppets
Hosokawa Hanzo Yorinao of Tosa published (Karakuri Zui), a book that explains how to build Japanese clocks and the inner mechanisms of 9 kinds of karakuri puppets, such as the tea-serving puppet, with diagrams of gears and springs. The tea-serving puppet moves forward when a teacup is placed on the tray it holds, stops when the cup is taken, and turns around and comes back when a cup is placed on it again. Whalebone was used for the springs.
4 sources and how they were checked
Where sources disagree:Year of publication: given as 1796 (Kansei 8; the National Diet Library catalog, the Nippon Encyclopedia and the World Encyclopedia), but the date of the preface is 1797 (spring of Kansei Teishi = Kansei 9; images of the same book). The catalog of another library says “Preface of Kansei 9 [1797]”.
1662–1768Confirmed in summariesSources disagreeJapan
Takeda Omi founds the karakuri (mechanical puppet) theater “Takeda’s Theater” (Japanese: Takeda no Shibai) in Dotonbori, Osaka
The first Takeda Omi used clockwork-based karakuri (mechanical devices) to open a theater devoted entirely to karakuri, “Takeda no Shibai” (Takeda’s Theater), in Dotonbori, Osaka. It showed the art of moving puppets and props by springs and water power at low prices. Because audiences wanted to know how the tricks worked, he also published a book explaining the mechanisms. The theater lasted about 100 years, and its techniques were passed on to joruri (Japanese puppet theater) and to festival float puppets.
3 sources and how they were checked
Where sources disagree:Year of founding: Kanbun 2 = 1662 (Britannica, the Osaka Biographical Dictionary, the Encyclopedia of Theater)/Kanbun 4 = 1664 (the Introduction of A Study of Takeda Karakuri; Chapter 8 of the same book says 1662).
What the figure shows:A mechanical doll's direction, whether it is moving, and whether it holds a tea bowl determine exactly 1 next action, so the same situation always produces the same movement.
041768–1774 · Automata
A writing doll with swappable steps
How do you build a doll whose sentence can be changed?
From 1768 to 1774, the watchmaker Pierre Jaquet-Droz, his son Henri-Louis, and Jean-Frédéric Leschot built three automata: , “The Musician” and “The Draughtsman”. They write with a quill, draw pictures and play an organ, and they are still in the Neuchâtel Museum of Art and History in Switzerland.
writes short sentences of up to 40 characters. Which sentence it writes is said to be set by the arrangement of knobs that choose the cams (discs with bumps; as a disc turns, a rod moves with the bumps) that move the pen. The result changes with the order in which parts of fixed shape are used. It is the same idea as a later program.
In the figure on the right, press the knobs to rearrange the order, then press "Write". The shapes of the letters stay the same, and only the arrangement changes the sentence.
pen position (x, y)= (radius of cam x, radius of cam y)
cam
a disc that pushes a rod according to its radius as it turns
knob arrangement
which cam is used in which order
The model and the real thing
The letter shapes and the mechanism in the figure are an example made for this site, not a copy of the real inner workings of . The two lines below show the movement of the pen position (=the cam radius).
Disagreement about the year:The museum gives 1768–1774 for the three automata, the caption of a Britannica picture gives about 1772 for the writing doll, and a watch-industry site gives 1775 for . In a September 2026 notice from the museum, was under repair because of a faulty part.
Sources & confidence (1)A writing doll with swappable steps
1768–1774Confirmed in summariesSources disagree
The Jaquet-Droz automata: a boy who writes, a boy who draws, a girl who plays the organ (1768–1774)
The watchmaker Pierre Jaquet-Droz, his son Henri-Louis and Jean-Frédéric Leschot built three automata in La Chaux-de-Fonds between 1768 and 1774. The figures were named l’Écrivain (the Writer), la Musicienne (the Musician) and le Dessinateur (the Draftsman). Using clockwork, they write letters with a quill pen, draw pictures and play the organ. After touring Europe for a long time, the three were given to the city of Neuchâtel on May 1, 1909. They are now shown in demonstrations every month at the Neuchâtel Museum of Art and History in Switzerland (the name as Britannica writes it). However, according to a notice on the museum’s website that we saw on September 23, 2026, l’Écrivain cannot be run because of a faulty part and is being repaired.
3 sources and how they were checked
Where sources disagree:Dates: the museum gives 1768–1774 as the years the three were made, but Britannica’s figure caption dates the writing figure to c. 1772, and a watch-industry website dates l’Écrivain to 1775. As for the number of parts of l’Écrivain, the number of letters it can write and the number of lines, among the sources we saw only the watch-industry website gives them, and its figures vary even within the same page.
What the figure shows:Keeping the parts that form letters unchanged, but changing which parts are used and in what order, changes the sentence written. This is the same idea used in later programs.
051770–1836 · Spectacle
Inside the chess-playing doll's box
Was there really a chess-playing machine in the 18th century?
Around 1770, at the court in Vienna, Kempelen built and showed a machine for Empress Maria Theresa: a doll in Turkish dress that played chess on top of a box. The doll toured Europe and America, but a chess master was actually hidden inside the box. In 1784 a book appeared saying there was a person inside. A book of 1821 explained with a diagram how the person inside slid his body out of sight while the doors were opened one after another to show the interior.
In the figure on the right, open the doors. The person inside moves to the side that is closed. What happens if you open both at once?
In 1836, Poe argued that a pure machine would always win, yet this one sometimes lost, so a person must be moving it. His conclusion was right. But in 1950, Shannon called this reasoning , because a machine that follows fixed rules alone will lose if its rules are poor (you can check this with the Python program).
The machine was destroyed in a fire in Philadelphia in 1854. Some sources give 1769 as the year it was built.
What you think you knowThe popular story:In the 18th century there was a thinking machine that played chess The original source says:In fact a person was hiding inside. According to the book by his friend Windisch (1784), Kempelen began from the start by hinting to the Empress that he could build a machine that fooled the eye even better, and he called this machine .
Sources & confidence (2)Inside the chess-playing doll's box
1770–1854Verified in the originalSources disagree
Kempelen’s : a person was hiding inside
Kempelen, a nobleman from Pressburg in Hungary, built a machine at the court in Vienna for Empress Maria Theresa: a figure in Turkish dress that played chess on top of a cabinet. It toured Europe and America and amazed many people, but in fact a skilled chess player was hidden in the cabinet and moved it. As early as 1784 a book was published saying that a person was hidden inside and playing, and in 1821 a book appeared that explained with diagrams how the person hid. The machine was destroyed in a fire in Philadelphia in 1854.
The popular story:People tend to say “in the 18th century there was a thinking machine that played chess” The original source says:In fact a person was hidden in the cabinet and operated it. According to the book (1784) by Kempelen’s contemporary friend Windisch, Kempelen began the work by hinting to the Empress at the idea of , and he called the device . Poe (1836) also quotes him as saying that it was a , and that it looked wonderful because of the boldness of the idea and his skill in choosing the way to create the illusion.
6 sources and how they were checked
Where sources disagree:Year of construction: there is a 1769 account (the HNF museum says “he showed it to the Empress in 1769”, and Poe 1836 says “invented in 1769”) and a 1770 account (Linda Hall Library). Windisch (1784) writes “he promised it in 1769 and finished it in 6 months”. Place of the fire: HNF says the “Chinese Museum” and the Linda Hall Library says “Peale’s Museum” (both in Philadelphia, 1854). Timing of the exposure: it came in stages, with Thicknesse’s claim in 1784, the book of analysis in 1821 and Poe in 1836. The story that the owner’s son Mitchell revealed everything in a magazine in 1857 could not be checked here because we could not open the original magazine (Google Books had hit its search limit, and HathiTrust would not let us view it). Its only basis is Wikipedia, so it is unconfirmed.
Poe argues that a machine alone could not play chess, so a person must be moving it from inside
Edgar Allan Poe wrote an essay about the Chess-Playing Turk figure. Babbage’s calculating machine reaches its answers by a fixed procedure, but chess changes with the opponent’s moves, so Poe argued that a machine alone could not play it and that a human mind was running it. He also pointed out that a real machine should always win, yet the Turk sometimes loses.
The popular story:People tend to say “Poe saw through the trick with brilliant deduction” The original source says:His conclusion that a person was inside was right. But in 1950 Shannon criticized Poe’s argument, which starts from the premise (a machine that no person moves should not lose) and concludes that since the Turk sometimes loses, a person must be moving it, as .
What happened next:In 1950 Shannon proposed in a paper a way to have a general-purpose computer play reasonably good chess by a program, and pointed out that Poe’s argument does not hold. In May 1997, IBM’s computer Deep Blue beat the world champion of the time 3.5 to 2.5 in a six-game match in New York (IBM’s account).
What the figure shows:A person hides inside the chess-playing doll's cabinet, moving to the closed side as the doors are opened one after another. Opening both doors at once reveals the person.
061822 · Difference Engine
Number tables without multiplying
Can we hand the toil of repeating the same calculation over to a machine?
In 1822, in an open letter to Davy, president of the Royal Society, the Englishman Charles Babbage described a plan for a machine that would automatically calculate, and even print, tables of numbers used for logarithms and astronomy. At the start of the letter he writes that, out of the great toil of repeating the same calculations, he conceived a machine to stand in for one of the lowest workings of the human intellect. This later came to be called the Difference Engine.
The key is the difference (the difference between neighboring numbers). The squares 1, 4, 9, 16 ... have differences 3, 5, 7 ..., and the difference of the differences is always 2. So if you repeat "add the second difference to the difference, add the difference to the number", you can keep producing the table without using multiplication. Turning the row of gears in the figure on the right once moves the table forward by one row. For a cubic formula, there is one more row of gears.
The words Difference Engine do not appear in the title of the letter. It is a name that came into use later.
Sources & confidence (1)Number tables without multiplying
3 July 1822Verified in the original
Babbage announces a machine that calculates and prints tables of numbers automatically (the Difference Engine)
In an open letter to Davy, the president of the Royal Society, Charles Babbage of Britain described his plan for the Difference Engine. It is a machine that automatically calculates the tables of numbers used for logarithms and astronomy by repeatedly adding the differences between neighboring numbers, and even prints them. At the start of the letter he wrote that, out of the great drudgery of repeating the same calculations, he had thought of a machine that could take the place of one of the lowest workings of the human intellect.
What the figure shows:The differences between the differences of square numbers are always 2. Repeatedly adding differences can therefore keep producing a number table without multiplication.
071843 · Analytical Engine
Bernoulli numbers by repeating steps
Can we write the steps of a calculation and hand them to a machine?
Babbage's next idea was the , which would be given its steps by punched cards and could do any calculation (it was never built). In 1843, Ada Lovelace translated a paper explaining this machine into English and added notes about three times as long as the original. She signed them only A.A.L.
In Note E she called a group of operations that is repeated many times a cycle, and also explained nesting, a repetition inside a repetition. In Note G she showed in detail, with a formula and a table, the steps by which the engine would calculate a sequence of numbers called Bernoulli numbers one after another. With n=1 for B₁, n=2 for B₃, n=3 for B₅, the same formula is repeated while n changes, and each earlier answer is used in the next calculation. It is an algorithm (clearly written steps for solving a problem) with what we now call a loop. In the figure on the right, press "Repeat once".
Bernoulli numbers (the numbering is as in the Notes)
What you think you knowThe popular story:Lovelace flatly said machines have no creativity The original source says:In Note G, just before writing that the engine has , she wrote that new things tend to be overrated at first and then underrated in reaction, so we should be careful. She had already described the boom-and-winter pattern in 1843.
The world's first programmer?
Whether to call her that is disputed. According to Babbage's own recollection (1864), she chose the examples and did the calculations, but Babbage took on the Bernoulli-number part, and she found a serious mistake and sent it back. Some see the table in Note G as close to what we now call an execution log.
Note A also contains a forecast, on the condition that the relations between musical pitches can be expressed in the machine's symbols: (spread 19 of this chapter).
Sources & confidence (2)Bernoulli numbers by repeating steps
1843Verified in the originalSources disagree
Ada Lovelace publishes Babbage’s Analytical Engine description with long notes of her own
Ada Lovelace translated into English an account of Babbage’s (a machine designed to calculate anything, given its steps by punched cards; it was never built), written in French by the Italian engineer Menabrea. She published it with notes about three times as long as the original. It was signed only A.A.L. In Note G she wrote that the machine does not pretend to originate anything; it can do whatever humans know how to order it to do.
The popular story:Lovelace tends to be quoted as having flatly declared “machines cannot create” The original source says:Just before that sentence in Note G, she argues that we should be careful because new inventions are easily overrated, and are then easily underrated in reaction. The words were said in a context of warning against excessive expectations.
What we still don’t know:What it means for a machine to have is still unsettled. (In 1950 Turing took up this sentence as and replied that machines often surprise him.)
6 sources and how they were checked
Where sources disagree:Opinions differ on whether to call Lovelace the “world’s first programmer”. The Computer History Museum says “often called that, but biographers debate it”. Aspray (ed., 1990), cited by Nilsson (2010), says there is “no basis” for it. A Bodleian Libraries article (2018) writes that the table in Note G is often called “the first program” but is closer to a record of an execution. Babbage’s own recollection (1864, p. 136) says that the examples and calculations were hers, but that Babbage took on the part about Bernoulli numbers and she found a mistake. This site does not decide either way.
In Note A, Lovelace argued that the Analytical Engine should be able to handle not only numbers but anything whose relations can be expressed in symbols. As an example, she wrote that if the relations between pitches of sound could be expressed in the machine’s symbols, the machine might compose music of any degree of complexity and length, elaborate pieces.
What happened next:The Analytical Engine itself was never built. About 110 years later, on August 9, 1956, at the University of Illinois in the United States, students performed the first three movements of a string quartet composed with the computer ILLIAC I (the Illiac Suite) (the university museum’s account; it was completed by the end of 1956, though some sources write 1957).
What the figure shows:Lovelace's Note G describes repeating the same formula while changing n and using each earlier answer in the next calculation. Today, this would be called an algorithm with a loop.
081854 · Algebra of logic
An algebra of only 0 and 1
Can "and", "or" and "not" be written as calculations with formulas?
In 1854, George Boole published . His aim was to express the laws of the mind's workings when people reason by means of calculation with symbols, like algebra, and to build a theory of logic and probability.
Boole noticed that the symbols of logic obey x×x=x (x² =x). Among numbers, only 0 and 1 satisfy this. So he considered an algebra in which symbols take only the values 0 and 1 (page 37). He wrote the collection of things that are not x as 1 − x, and showed that x(1 − x)=0 expresses the old rule that nothing can be x and not x at the same time (the law of non-contradiction) (pages 48–49).
In the figure on the right, move x. Only 0 and 1 give x² =x. If you make tables for "and", "or" and "not" with 0/1 switches, they match the logic circuit tables studied in Information I (Japan's required high-school informatics course).
x·y (and)、1 − x (not)、x+y − x·y (or)
x, y
values 0 or 1
x+y − x·y
“or” written in today's notation
What you think you knowThe popular story:Boole created 0-and-1 logic for computers The original source says:The book's aim was to write the laws of the mind's workings in reasoning as symbols. Searching the text by characters, the word machine does not appear in the book. It was engineers about 80 years later who applied it to electric switching circuits (spread 10 of this chapter).
Sources & confidence (1)An algebra of only 0 and 1
1854Verified in the original
Boole’s : expressing the laws of reasoning in an algebra of 0 and 1
George Boole, professor of mathematics at Queen's College, Cork, published his book . Its aim was to express the laws of thought by which humans reason (think in a logical sequence) as calculations with symbols, like algebra, and to build the theories of logic and probability on that (Chapter 1, Section 1). Boole noticed that 0 and 1 are the only numbers that satisfy x×x = x (x² = x). He argued that if you consider an algebra in which the symbols x, y and z take only the two values 0 and 1, it has the same form as the laws of logic (page 37). This algebra of 0 and 1 was later called Boolean algebra, and became the basis of the logic circuits (AND, OR, NOT) studied in Information I (Japan’s required high-school informatics course).
The popular story:Boole tends to be taken as having created the logic of 0 and 1 for computers (a university page also writes that he was ) The original source says:What the book gives as its aim is to express the laws of thought people use when they reason by symbolic calculation, and to build the theories of logic and probability (Chapter 1, Section 1). In the text searches we ran on this site, the word does not appear in the book. It was engineers about 80 years later who applied it to electrical switching circuits (record → Akira Nakashima and Masao Hanzawa of NE…).
What the figure shows:Only 0 and 1 satisfy x² = x. Calculating with just 0 and 1 produces tables for AND, OR, and NOT that match logic circuit tables.
091920–1942 · Robots
The “robot” and Gakutensoku's drum
When, and as what kind of being, was the robot born?
In 1920, the Czech writer Karel Čapek published the play . The “robot” is an artificial person made from artificial materials, mass-produced to work, and the name is coined from a word for labor. In Karel's own account, when he was struggling to find a name, his brother Josef, a painter, suggested: .
In 1928, Makoto Nishimura, a biologist who was an editorial writer at the Osaka Mainichi newspaper, built an artificial human named “Gakutensoku”, meaning (translated), and showed it at an exposition in Kyoto. It was powered by compressed air. A shaft covered in many wart-like bumps turned, pressing particular rubber tubes for particular lengths of time to stop or let air through. Like the pins of a music-box drum, the order of the bumps is the program of its movements (research report of the Osaka Science Museum).
In the figure on the right, attach and remove the bumps on the drum. You can check the order in which the expression changes.
In 1942 the science fiction writer Asimov wrote the in his short story . In the story, the vagueness of the wording of the rules, and conflicts between the laws, drove the plot.
What you think you knowThe popular story:Gakutensoku was Japan's first robot The original source says:The Osaka Science Museum's material says it is (translated). The original is said to have gone to Germany and been lost; what exists now is a reconstruction from 2008.
Sources & confidence (3)The “robot” and Gakutensoku's drum
1920–1921Verified in the originalSources disagree
The word “robot” is born in Čapek’s play
The Czech writer Karel Čapek published the play , in which artificial humans called “robots”, mass-produced from artificial materials, do the work. At the National Theatre in Prague it opened on January 25, 1921, and had been performed 63 times by 1927. “Robot” was coined from a word meaning labor, and in the story Karel himself wrote, it was his brother Josef, a painter, who gave the name.
The popular story:People tend to say “Čapek (Karel, the author) coined the word ‘robot’” The original source says:In the story Karel himself wrote, when Karel was at a loss for a name, his brother Josef, a painter, said, (as quoted by Nilsson, in a research report of the Osaka Science Museum, and by Czech Radio). People also tend to say “it premiered at the National Theatre in Prague” → According to Czech Radio, a local amateur theater group had performed it earlier.
What we still don’t know:We have not been able to open the original text of the story Karel himself wrote (a newspaper column; the year has not been confirmed in the sources).
4 sources and how they were checked
Where sources disagree:The first performance: the National Theatre archive treats its own production as the 100th anniversary of the “world premiere”. Czech Radio, on the other hand, writes that an amateur theater group in Hradec Králové performed it before the National Theatre (the date could not be confirmed from the article).
Makoto Nishimura builds “Gakutensoku”, a large humanoid with changing facial expressions
The biologist Makoto Nishimura, then an editorial writer for the Osaka Mainichi Shimbun, built a humanoid (robot) named “Gakutensoku”, a name meaning (translated). It was shown at the 1928 Kyoto Grand Exposition commemorating the Imperial Enthronement. Using compressed air and rubber tubes, it moved its eyes, eyelids, cheeks, mouth, neck, both arms and chest, and changed its expression. It is said to have later gone to Germany and been lost. The Osaka Science Museum restored it in 2008.
The popular story:It tends to be called “Japan’s first robot” The original source says:The Osaka Science Museum’s materials say (translated) (research report) and (translated) (press release). The story of its disappearance in Germany also ends with the same (translated), so it is not clear.
What we still don’t know:Where in Germany and how the original Gakutensoku ended up is not known (the museum, too, writes (translated)).
Asimov’s (1942): three rules that robots follow in his stories
The science fiction writer Isaac Asimov set out the three rules that robots obey, the , in clear form in the short story , published in the March 1942 issue of the magazine Astounding. (1) A robot may not injure a human being or, through inaction, allow a human being to come to harm. (2) A robot must obey orders given by humans, except where that would conflict with the First Law. (3) A robot must protect itself, as long as that does not conflict with the First or Second Law. In the story, vagueness of wording and conflicts between the laws became the seeds of the plot, for example a robot whose Third Law (self-protection) has been strengthened gets caught in a bind when priorities between the laws collide (SFE). Asimov later added the , that a robot must not harm humanity as a whole (stated clearly in a 1985 work). The three laws went beyond science fiction and came to be discussed in debates about robots and AI (Britannica).
The popular story:People tend to think “Asimov came up with the three laws by himself” The original source says:Asimov himself said that John W. Campbell Jr. put the three laws together in a conversation in December 1940, and Campbell thought the laws were already contained in Asimov’s early robot stories (SFE). Also, in the stories the three laws are not portrayed as perfect rules, but as material for problems caused by vagueness of wording and clashes between the laws.
What we still don’t know:Even if rules are set in words, the results change depending on how words such as and are defined (the many stories about definitions that SFE lists). The same challenge remains when we write in words the rules we want today’s AI to follow (this site’s view).
What the figure shows:Gakutensoku's actions are set by the order of bumps on a rotating shaft. Like pins in a music box, their arrangement acts as a program.
101936 · Japan · Circuit algebra
Calculating switch circuits
Can we work out whether a bulb lights without drawing the circuit?
In December 1936, Akira Nakashima and Masao Hanzawa of Nippon Electric (NEC) published in the journal of the Institute of Electrical Communication Engineers of Japan a theory for designing relay circuits (electrically operated switches), used in telephone exchanges and elsewhere, by calculating with symbolic formulas. They described a contact by how hard it is for electricity to pass: 0 if closed, infinity if open. Two contacts in series were written A+B, and in parallel A×B. Then+and × followed rules quite different from ordinary arithmetic. This was the same thing as Boolean algebra, but Nakashima did not know Boolean algebra at the time.
In the figure on the right, press the switches. In the modern notation (connected=1), series means "and" (×) and parallel means "or" (+). In the 1936 notation (connected=0), series becomes+and parallel becomes ×. Either way, the result of whether the bulb lights is the same.
today: series A·B, parallel A+B 1936: series A+B, parallel A × B
A, B, C
switches
+and ×
calculations done with 0 and 1 (1+1 is 1)
What you think you knowThe popular story:Shannon started the theory of designing circuits with Boolean algebra The original source says:Akira Nakashima and Masao Hanzawa published a theory of calculating relay circuits with formulas in the December 1936 journal of the Institute of Electrical Communication Engineers. The museum of the Information Processing Society of Japan describes it as the same content, two years earlier than Shannon.
December 1936Verified in the originalSources disagreeJapan
Akira Nakashima and Masao Hanzawa of NEC publish a theory for calculating relay circuits with formulas
Akira Nakashima and Masao Hanzawa, engineers at Nippon Electric Company (NEC), published in the journal of the Institute of Electrical Communication Engineers a theory for designing the relay circuits (switches operated by electricity) used in telephone exchanges and similar equipment by calculating with formulas of symbols. They discovered that if series and parallel connections of switches are written like addition and multiplication of symbols, they follow rules different from ordinary arithmetic. This had the same form as Boole’s logical calculus of 1854 (Boolean algebra), but Nakashima did not know Boolean algebra at the time. It is an idea that became the basis of later computer circuit design.
The popular story:English-language histories often say “the theory of designing circuits with Boolean algebra was begun by Shannon” The original source says:Akira Nakashima and Masao Hanzawa of NEC had published a theory of calculating relay circuits with formulas in the December 1936 issue of the journal of the Institute of Electrical Communication Engineers (the museum of the Information Processing Society of Japan writes that it is the same content, two years before Shannon).
4 sources and how they were checked
Where sources disagree:On the university and year of Shannon’s master’s thesis, MIT’s records give “MIT Department of Electrical Engineering, 1940” (the year of the degree). Nilsson (2010) writes “a 1937 master’s thesis at Yale University”. Many sources say it appeared in a journal as a paper in 1938, but we have not confirmed this on this site. “Nakashima was 2 years ahead of Shannon” is how the museum of the Information Processing Society of Japan puts it, and we have not confirmed on this site which papers were compared.
What the figure shows:Switch circuits can be calculated by expressing series and parallel connections with + and ×. Whether using the 1936 notation (connected = 0) or today's notation (connected = 1), the answer about whether the lamp lights is the same.
111936 · A model of computing
Calculating with just a tape and a table
What does it mean for something to be computable?
In 1936, Alan Turing published the paper . He reduced the steps a human follows when calculating with paper and pencil to a that runs on a tape divided into squares (in place of paper), a head that reads and writes one square at a time, and only a finite number of states. He defined the numbers this machine can write out as .
The figure on the right is that machine. The head reads one symbol on the tape, looks it up in the rule table, rewrites the symbol, moves one square left or right, and moves to the next state. This alone can add 1 to a binary number. You can also choose the first example from page 233 of the paper, a machine with four states that writes 0 and 1 alternately.
The paper went on to show that if a description of another machine is read from the tape, one machine (the universal machine) can carry out any calculation, and that no fixed procedure exists that always decides whether a logical formula is provable.
(state, symbol read) → (symbol to write, direction to move, next state)
state
one of a finite number of marks inside the machine
table
the list of action rules (the equivalent of today's program)
What you think you knowThe popular story:Turing designed the computer in 1936 The original source says:The paper's is a model in the head that simplifies the steps of a person doing calculations, and the “computer” in the paper meant a person who calculates. The name is not in the paper either; it was given in Church's review the next year.
Sources & confidence (1)Calculating with just a tape and a table
1936Verified in the originalSources disagree
Turing, : defining what it means to be with a machine in the head
Alan Turing published the paper . He simplified the steps of a person calculating with paper and pencil down to a that has a tape divided into squares (in place of paper), a head that reads and writes one square at a time, and only a finite number of states (Sections 1 and 9). He defined a number whose decimal digits this machine can write out as . He further showed that one machine (a universal machine) can compute any computable sequence if it receives the description of another machine on its tape (Section 6). And he showed that there is no method that always decides, by a fixed procedure, whether a logical formula can be proved (the answer to the decision problem) (Section 11). The next year this model was named the , and it is regarded as a foundational model of the theory of computation and of computer science.
The popular story:People tend to take it that “Turing designed the computer (the Turing machine) in 1936” The original source says:The machine in the paper is a model in the head, a simplification of the steps of a person calculating with paper and pencil (Sections 1 and 9). The “computer” in the paper means a human who calculates, and on page 250 it is written as he. The name is not in the paper either; his own names were automatic machine and the like. It was Church’s review the next year that named it (SEP).
9 sources and how they were checked
Where sources disagree:Year: the received date on the printed page is May 28, 1936 and the date it was read to the society is November 12, 1936. The year of the volume it appeared in (Vol. 42) is 1937 in the publisher’s registration (Crossref) and in the King's College catalog, and SEP gives “1936–7”. This site gives both: “1936 (received and presented), journal volume 1936–37”.
What the figure shows:A simple machine that reads 1 tape square, rewrites it, and moves can calculate using only a table of rules. Turing called numbers that this machine could write out “computable.”
121943 · Formal neuron
Turning a nerve into a switch
What does a brain's nerve cell look like when written as a formula?
In December 1943, McCulloch and Pitts published the paper . Since the activity of a nerve cell (neuron) is (it fires or it does not), they reasoned that the workings of a network of nerve cells (a neural network) can be written in two-valued logic. It is regarded as the starting point of neural network research.
Their assumptions include that a neuron fires when a certain number of synapses are stimulated at the same time, that a single active inhibitory synapse stops it firing, and that the way the network is connected does not change. In today's words, this is a formal neuron that adds up its inputs and compares the sum with a threshold. Try it in the figure on the right. Threshold 2 gives AND, 1 gives OR, and an inhibiting input gives NOT. XOR (exactly one of the two) cannot be made with one neuron, but can be made by connecting three.
y=1 (when x₁ +x₂ + … ≧ θ and the inhibiting input is 0), otherwise 0
x
input (0 or 1)
θ
threshold
inhibiting input
if even one is 1, the output is always 0
What you think you knowThe popular story:The 1943 model had fixed connections, and learning only came with Hebb in 1949 The original source says:The 1943 paper also dealt with learning. It considered changes in which new synapses form, and wrote that such changes can be replaced by a network with loops (page 124).
The model and the real thing
The paper itself notes that the , the claim that a learning network can be replaced by a network whose connections do not change, is not an explanation of the facts of the real brain (page 117).
Sources & confidence (1)Turning a nerve into a switch
December 1943Verified in the original
The McCulloch and Pitts paper: writing the brain’s nerve cells as a circuit of switches that fire or do not fire, in formulas
Warren McCulloch and Walter Pitts published the paper . Because the activity of a nerve cell (neuron) is (it fires or it does not), they reasoned that the workings of a neural network can be described by propositional logic (logic with only two values, true and false). As premises for the calculation they set that firing is all-or-none, that a neuron fires when a certain number of synapses are stimulated at the same time, that if even one inhibitory synapse is active the neuron does not fire, and that the structure of the network does not change with time (page 118). They further wrote that if a tape and a reading device are added, this network can compute the same numbers as a Turing machine (page 129). It is regarded as a starting point of later research on artificial neurons.
The popular story:(1) General explanations often introduce it in the order “McCulloch and Pitts in 1943 = a model of nerves; Hebb in 1949 = a mechanism for learning” (for example, page 2 of the Nobel Prize explainer) The original source says:The 1943 paper also deals with learning. Taking the formation of new synapses as the simplest kind of change, it assumes that when the neuron fires and the endings are excited at the same time (), the endings become ordinary synapses, and it writes that such a change can be replaced by a network with loops (Theorem VII) (page 124). However, as a premise for the calculation, it sets that the structure of the network does not change (page 118). (2) Some summaries write that the paper (Nilsson, page 34) → On page 129 of the paper, it says that with a tape and a reading device the network can compute the same numbers as a Turing machine, and that a network without a tape can compute only some of them.
What we still don’t know:The paper itself cautions that the , that a learning network can be replaced by a network whose structure does not change, is not an explanation of facts about the real brain (page 117). That real neurons do not work exactly as these premises assume (all-or-none, unchanging structure) can be used as an example for understanding the difference between a model and the real thing.
What the figure shows:Even a switch that just adds inputs and compares them with a threshold can act as AND or OR by changing that threshold, and as NOT with an input that blocks firing. XOR cannot be made with 1 such switch, but can be made by connecting 3.
This is the same mechanism as "Try it", written as Python code. Press ▶ Run and the result appears below. Change the numbers and run it again.
u02_mcculloch_pitts.py
131943 · Time and memory
Something cold feels hot for a moment
Can a network of switches remember what came before?
Page 122 of the same paper has a strange example. If you touch something cold to the skin for a moment and take it away, it feels hot, but if you keep it there longer, you feel only cold. The paper wrote the connections between the neurons that receive input at the skin (heat, cold) and the neurons that produce the feeling (hot, cold) as formulas, and explained this illusion. A signal is delayed by one tick each time it passes through a connection. By stacking delays, a network can remember a little of what came just before.
In the figure on the right, change how long the cold touch lasts. For a moment, the "feels hot" side fires after the touch is gone; for a long touch, the "feels cold" side fires.
Page 124 says that if signals form a loop, activity can circle the loop forever. The neuron in the loop in the figure keeps firing once it fires, until a stop signal arrives. It is the simplest memory, one that can hold on to things from long ago.
hot(t)=heat(t−1) or (cold(t−3) and not cold(t−2)) cold-feeling(t)=cold(t−2) and cold(t−1)
t
time (1 tick=the delay of one connection)
heat, cold
firing of the receiving side at the skin
hot, cold-feeling
firing of the feeling side
What you think you knowThe popular story:McCulloch and Pitts showed that neural networks can do any calculation The original source says:On page 129 of the paper they write that with a tape and a reading device added, the network can compute the same numbers as a Turing machine, and without the tape it can compute only some of them.
Sources & confidence (1)Something cold feels hot for a moment
December 1943Verified in the original
The McCulloch and Pitts paper: writing the brain’s nerve cells as a circuit of switches that fire or do not fire, in formulas
Warren McCulloch and Walter Pitts published the paper . Because the activity of a nerve cell (neuron) is (it fires or it does not), they reasoned that the workings of a neural network can be described by propositional logic (logic with only two values, true and false). As premises for the calculation they set that firing is all-or-none, that a neuron fires when a certain number of synapses are stimulated at the same time, that if even one inhibitory synapse is active the neuron does not fire, and that the structure of the network does not change with time (page 118). They further wrote that if a tape and a reading device are added, this network can compute the same numbers as a Turing machine (page 129). It is regarded as a starting point of later research on artificial neurons.
The popular story:(1) General explanations often introduce it in the order “McCulloch and Pitts in 1943 = a model of nerves; Hebb in 1949 = a mechanism for learning” (for example, page 2 of the Nobel Prize explainer) The original source says:The 1943 paper also deals with learning. Taking the formation of new synapses as the simplest kind of change, it assumes that when the neuron fires and the endings are excited at the same time (), the endings become ordinary synapses, and it writes that such a change can be replaced by a network with loops (Theorem VII) (page 124). However, as a premise for the calculation, it sets that the structure of the network does not change (page 118). (2) Some summaries write that the paper (Nilsson, page 34) → On page 129 of the paper, it says that with a tape and a reading device the network can compute the same numbers as a Turing machine, and that a network without a tape can compute only some of them.
What we still don’t know:The paper itself cautions that the , that a learning network can be replaced by a network whose structure does not change, is not an explanation of facts about the real brain (page 117). That real neurons do not work exactly as these premises assume (all-or-none, unchanging structure) can be used as an example for understanding the difference between a model and the real thing.
What the figure shows:A signal is delayed by 1 time step each time it passes through a connection, so stacking delays stores information from a short time ago. A loop can keep it stored indefinitely.
This is the same mechanism as "Try it", written as Python code. Press ▶ Run and the result appears below. Change the numbers and run it again.
u02_mp_time.py
141946 · Electronic computer
Math robot or electronic brain?
What was the first electronic computer built for, and how was it presented?
In February 1946, the US War Department announced ENIAC, an electronic computer built at the University of Pennsylvania. It had about 18,000 vacuum tubes and weighed 30 tons. It was a machine for calculating firing tables (tables of how shells fly) for guns and bombs. According to the announcement, it could add in 1/5000 of a second and multiply two 10-digit numbers in 1/360 of a second. Its steps were set up by changing the connections of switches and cables.
A firing-table calculation repeats two steps: move the position forward by the speed over a very short time, then change the speed because of gravity and air resistance. In the figure on the right, the finer you make each step, the more accurate it gets, and the more calculation there is. In a 1974 lecture by Burks, who demonstrated it to the press, a shell flight of 30 seconds took a human calculator (the job was also called a computer then) 3 days, and ENIAC 20 seconds. The announcement called it and also wrote that .
x ← x+vxΔt、vx ← vx − k·v·vxΔt (the same for the vertical direction, with gravity g subtracted)
Δt
time of one step
v
speed
k
strength of air resistance (the numbers in the figure are examples chosen by this site)
What you think you knowThe popular story:ENIAC was announced as an electronic brain The original source says:The War Department's announcement went out of its way to say that it . The words were a phrase made up by newspaper headlines, and in the same year Hartree in Britain also protested against a headline.
Sources & confidence (1)Math robot or electronic brain?
15 February 1946Verified in the originalSources disagree
The ENIAC announcement: the Army release says ... , while the newspapers say
The US War Department announced ENIAC, an electronic calculating machine developed at the Moore School of Electrical Engineering of the University of Pennsylvania. According to the release, it had about 18,000 vacuum tubes, took up a room of 30 by 50 feet, weighed 30 tons, and was 1000 times faster than the most advanced general-purpose calculating machine of the time. Work began in July 1943 to produce firing tables (ballistic tables) for guns and bombs, and it was finished in the autumn of 1945. The calculation steps (the program) were set by reconnecting switches and cables by hand (Weik 1961). In those days people who did calculations were also called “computer”, and the release says that about 200 trained “computer” were needed to produce firing tables. The release calls ENIAC , and also records that .
The popular story:People tend to think “ENIAC was announced as an ‘electronic brain’” The original source says:The War Department’s release calls it , and deliberately records that and that it . The word was added by newspaper headlines, and in the same year Hartree in Britain also protested against the headlines (Martin 1995).
4 sources and how they were checked
Where sources disagree:Date: Martin (1995) gives the public announcement as February 14, 1946; the release is for the radio on the evening of February 15, 1946 and the morning papers of February 16; Weik (1961) gives the formal unveiling as February 15. Cost: the release says about $400,000 (an estimate including research and development), while Weik gives a total contract of $486,804.22. Martin also writes “Saturday, February 14, 1946”, but February 14, 1946 was a Thursday and the Saturday was February 16 (calculated from the calendar on this site).
What the figure shows:ENIAC calculated tables of artillery shell paths. It repeatedly updated position and speed over short intervals; smaller steps improved accuracy but increased the number of calculations.
151949 · Learning rule
Used connections grow stronger
How does a neural circuit learn from experience?
In 1949, on page 62 of , the psychologist Donald Hebb set out a hypothesis. When cell A repeatedly or persistently takes part in firing cell B, some change takes place in one or both cells, so that A's influence in firing B increases. The idea is that the more a connection is used, the stronger it gets. On the same page he also wrote that there is no direct evidence for such a mechanism.
The figure on the right is the simplest example. B always fires when a food signal arrives. The connection from A (the sound of a bell) to B is weak at first. Each time A and B fire together, the connection gets stronger. Once it passes the threshold, the bell alone makes B fire. The bell and the food are this site's analogy.
This idea is called the , and it became one of the starting points both for research on how the brain works and for learning methods in artificial neural networks.
w ← w+η·xA·yB
w
strength of the connection from A to B
η
how fast the connection strengthens (learning rate)
xA, yB
1 when A or B fires
What you think you knowThe popular story:Hebb said cells that fire together wire together The original source says:The book's wording is that A . The slogan fire together, wire together was spread in lectures by the neuroscientist Carla Shatz.
Hebb’s : the assumption that nerve connections that are used often become stronger
The psychologist Donald Hebb published the book . In on page 62, he assumed that when cell A repeatedly or persistently takes part in the process of making cell B fire, some change happens in one or both cells, and A’s efficiency in firing B increases. In other words, the more a connection is used, the stronger it becomes. On the same page Hebb himself notes that there is no direct evidence for the mechanism. This idea is called the , and it became one of the starting points of both research on how the brain works and the learning methods of artificial neural networks.
The popular story:People often say “Hebb said that cells that fire together wire together” The original source says:The passage on page 62 of the book says that when A ; it is not “at the same time”, but A that . In the searches we ran inside the book on this site, the words fire together and wire together were not found. This short slogan was used by the neuroscientist Carla Shatz in a talk and spread through her Scientific American article (her own testimony and a Stanford University web page).
What we still don’t know:In 1949 Hebb wrote that the mechanism (the growth of synaptic knobs) was the but that there was no direct evidence (page 62). Later, experiments found a similar phenomenon (Nilsson). It can be used as an example of an idea put forward as an assumption that was confirmed later.
What the figure shows:Every time A and B fire together, the connection from A to B grows stronger. Once the threshold is crossed, the bell alone can make B fire.
Connection strength w at each round
This is the same mechanism as "Try it", written as Python code. Press ▶ Run and the result appears below. Change the numbers and run it again.
u02_hebb.py
161949–1954 · Machine translation
Nearby words fix the meaning
What is missing for a computer to translate language?
In 1949, Warren Weaver of the Rockefeller Foundation circulated to acquaintances a memorandum called , asking whether computers could translate language. If you read a book through a mask with a hole big enough for only one word, you cannot tell whether the word fast means quick or fixed in place. He presented the idea of context: if you widen the hole so that you can see N words on each side, the meaning is fixed.
In the figure on the right, change the width N of the hole. The example sentences and the table of clue words that fix the meaning are examples made for this site. When N is small, the clue falls outside the hole and the meaning comes out wrong.
In January 1954, IBM and Georgetown University held a public experiment translating Russian into English on the IBM 701 computer. It had 250 words and only 6 grammar rules. Dostert predicted that in five, perhaps three years, machine translation .
meaning=table(the nearest clue word within N words on each side)
N
width of the hole (how many words to look at on each side)
What you think you knowThe popular story:Machine translation would be solved in 3 to 5 years The original source says:The original announcement had a condition. At the same event it also stressed that it was not yet possible to put in a Russian book and get out an English book. The results of the next 10 years fell short of expectations, leading to the 1966 ALPAC report (Chapter 5).
Sources & confidence (3)Nearby words fix the meaning
15 July 1949Verified in the original
Weaver’s memorandum : the first call to ask whether calculating machines could translate languages
Warren Weaver of the Rockefeller Foundation wrote a memorandum titled on whether computers could be used for translation, and circulated it to people he knew. In 1947, in a letter to Professor Norbert Wiener of MIT, Weaver wrote that when he looks at an article in Russian, he says , and asked about the idea of translating by computer. But Wiener replied that, frankly, he thought there was little hope for translation by machine-like methods because , and the matter went no further. In the memorandum, Weaver gave the idea of context: if you read a book through a mask with a hole only one word wide, you cannot tell whether , but if you widen the hole so that N words before and after can be seen, the meaning is settled. He proposed studying the statistical properties of language. Weaver himself repeatedly cautions that his ideas may be naive. This memorandum is regarded as the start of the field of machine translation (Nilsson).
IBM and Georgetown University give a public demonstration of machine translation from Russian
At IBM’s headquarters in New York, the computer IBM 701 translated Russian sentences prepared by language researchers of Georgetown University into English in a few seconds. It was a small experiment with a vocabulary of 250 words and only 6 grammar rules, but it was reported prominently, including on the front page of the New York Times, and it became the trigger for money to flow into machine translation research.
The popular story:IBM’s announcement wrote , and it was widely reported The original source says:In fact it was a small experiment with 250 words and 6 rules for the sentences that had been chosen. Hutchins (2004) later wrote that other research groups disliked and .
Dostert’s forecast: in 5 years, perhaps 3, machine translation in important areas of several languages may well be a reality
On the day of the demonstration, Dostert of Georgetown University said that it had become clear that translation by electronic processing is possible. And he predicted that . At the same time, however, he stressed that it was not yet possible to feed in a Russian book and have an English book come out.
The popular story:People tend to say “he said machine translation would be solved in 3 to 5 years” The original source says:In the original announcement it came with limits: , and it . In the same place he also stressed that one could not yet . He also added the outlook that each field would begin with its own separate dictionary.
What happened next:According to Hutchins (2004), the impression that practical translation was near brought in a lot of research funding afterward. But the results of the following 10 years fell short of expectations, and the funders set up an investigation committee called ALPAC (report of 1966). Nilsson (2010) also writes that the research afterward was a disappointment.
What the figure shows:‘Fast’ may mean ‘rapid’; or it may mean ‘motionless’, so the word alone is not enough to decide its meaning. Seeing the N words before and after it resolves the meaning, but if N is too small, the clue falls outside the window and the meaning is misread.
This is the same mechanism as "Try it", written as Python code. Press ▶ Run and the result appears below. Change the numbers and run it again.
u02_context_window.py
171864–1950 · Games
Looking ahead to pick a good move
How should a computer choose its moves to play a game?
In 1864, Babbage wrote in his memoir that he had thought .
In March 1950, Claude Shannon of Bell Labs showed a method in the paper . Chess has about 30 moves per turn, and a game of about 40 moves comes to 10 to the 120th power possible games, so you cannot read them all. So you look ahead a few moves and rate the resulting position with a score f(P). Assuming you pick the move with the highest score on your turn and the lowest on your opponent's turn, you carry the scores back to the current position (today called the minimax method).
The figure on the right is a tree of the same shape as Figure 2 of the paper. Change the scores and see which move gets chosen.
best move=maxi minj f(MijMiP)
P
current position
Mi
your move
Mij
opponent's reply
f
evaluation function of a position
How scores are decided, and tic-tac-toe
The example scores in the paper are made by multiplying the difference in the number of pieces by weights (queen 9, rook 5, bishop and knight 3, pawn 1), adding them up, and then adding a little for weak pawn structure and the number of moves available.
Babbage tried to raise money by showing a tic-tac-toe machine as a spectacle, but gave it up. Tic-tac-toe can be read all the way to the end, and with best play from both sides it is a draw (you can check this with the Python program).
Sources & confidence (2)Looking ahead to pick a good move
March 1950Verified in the original
Shannon publishes the paper
Claude Shannon of Bell Labs in the US published a paper on a way to make a general-purpose computer play chess by a program. Because reading every move through to the end of the game takes an enormous amount of calculation and is impossible, he proposed a method of looking a few moves ahead, scoring how good each position is, and choosing the best move.
Babbage writes that he thought , and that he tried to put a tic-tac-toe machine on show
In his memoirs, Babbage wrote that he chose to have a machine play games that need only the head, such as tic-tac-toe, checkers and chess, as a test of his way of thinking. When he asked people, most answered that games of skill require human reason. A small number who knew mathematics admitted that a machine might be possible, but insisted that no such machine could be built because even the simplest game has countless combinations. Babbage believed that any game could be played by a machine, and tried to raise money for the Analytical Engine by putting a tic-tac-toe machine on show, but gave up when he learned that other shows were not making money.
What we still don’t know:We have not checked how far the drawings of the tic-tac-toe machine were actually carried out.
What the figure shows:Minimax scores positions several moves ahead, then carries those scores back to the current position, assuming the opponent chooses the smaller score and the player chooses the larger one.
This is the same mechanism as "Try it", written as Python code. Press ▶ Run and the result appears below. Change the numbers and run it again.
u02_tictactoe_minimax.py
181950 · The imitation game
Replacing a question with a game
How should we answer the question of whether machines can think?
In October 1950, Turing wrote in a paper that the question was , and replaced it with the . The interrogator communicates only in writing with two people in other rooms. It started as a game of guessing which of two people is the man, and he considered how often the interrogator would be wrong if a machine took the man's part.
The paper includes sample questions and answers. Asked to write a poem about the Forth Bridge, the respondent declines, saying it cannot write poetry. Asked to add 34957 and 70764, it pauses for about 30 seconds and answers 105621 (the correct answer is 105721; this site's calculation). He also wrote that a human pretending to be a machine would soon be spotted through slowness and inaccuracy at arithmetic. In the figure on the right, try to guess which of X and Y is the machine.
The year before, the brain surgeon Jefferson said in a lecture that unless a machine could write a poem from feelings it had itself felt, and know that it had written it, we could not agree that machine equals brain. Turing took up this lecture in his paper and answered it. In fact, Jefferson's own words were .
What you think you knowThe popular story:Turing proposed the Turing test The original source says:The paper calls it the , and the words do not appear in the paper. Nor is it a paper that answers whether machines can think. He replaced that question with a question about a game.
Lady Lovelace's Objection
The paper takes up Lovelace's note of 1843, that the machine does not pretend to originate anything, as . Turing replies that machines often surprise him. He also discusses answers to 9 other objections, and the idea of a that is taught and raised like a child.
Sources & confidence (2)Replacing a question with a game
October 1950Verified in the original
Turing publishes a paper discussing machine intelligence through the
The British mathematician Alan Turing published a paper that replaces the question with the . The original is a game in which an interrogator tries to guess, using only written exchanges, which of a man and a woman in another room is which. Turing turned it into the question of how often the interrogator would be wrong if a machine played the man’s part. The paper also discusses answers to 9 objections and the idea of a that is raised by education.
The popular story:It tends to be called the The original source says:In the paper it is called the , and the term does not appear in the body of the paper. Also, the paper tends to be thought of as an answer to → he himself wrote that this question is (page 442 of the printed pages) and replaced it with a different question using the game.
What we still don’t know:We have not confirmed on this site who first used the name , or when.
Geoffrey Jefferson, professor of neurosurgery at the University of Manchester, objected to equating calculating machines with the brain in a lecture titled . He said that a machine could not be accepted as equal to a brain unless it wrote a sonnet (a 14-line poem) or a concerto because of thoughts and emotions it felt itself, and was also aware that it had written it. In his conclusion he voiced concern about the new danger of personifying machines.
What we still don’t know:Even if machines come to write poems and music, there is no known way to check from outside the conditions Jefferson set (whether it created from feelings it felt, and whether it knows the work is its own).
What the figure shows:Turing replaced “Can machines think?” with a game asking whether a machine could be identified through written exchanges alone.
191950–2025 · Checking the forecasts
The 70% yardstick
What happened to Turing's forecast?
In his 1950 paper Turing wrote that in about 50 years an average interrogator, after five minutes of questioning, would have no more than a 70% chance of identifying correctly. In the same paragraph he also wrote that this was a conjecture, and that there is no harm in keeping it separate from established fact. On the radio in 1951 he spoke of a time when, would come from a person or a machine, and in a 1952 discussion, for a format that allows any questions, he answered .
The figure on the right is a yardstick with the year across and the share of correct identification up. According to a 2000 summary paper, no program had yet won the grand prize in the contests with prize money, and machines were usually spotted right away. In March 2025, researchers at a US university announced the share of five-minute conversations judged to be human: 73% for GPT-4.5 and 56% for LLaMa-3.1-405B (an announcement by one research group). Since the format is a choice between two, the shares of correct identification are 27% and 44%.
What you think you knowThe popular story:Fooling 30% of the judges means passing The original source says:The paper has no pass mark; it was his own conjecture about about 50 years later. A 2000 paper gives examples of it being retold backwards: by the , that is, computers fooling interrogators 70% of the time.
Other forecasts
In 1843 Lovelace wrote that the engine might compose music. A piece composed by a computer was performed in 1956 (some sources say 1957). In 1950 Shannon wrote of 8 machines, including a machine that translates language, one that adds instrument combinations to a tune, and one that reasons by logic, as . In (Tetsuwan Atom), whose serialization began in 1952, Atom's birthday in the story is April 7, 2003.
In 1951 Turing also spoke of a worry that if machines can think, they might think more cleverly than we do. In the lecture manuscript he introduced it with , and on the radio he said that the worry was .
Sources & confidence (5)The 70% yardstick
October 1950Verified in the original
Turing’s forecast:
In his 1950 paper, Turing set down his own forecast. In about 50 years, he wrote, computers could be made to play the imitation game well, and an average interrogator would have no more than a 70% chance of identifying correctly after 5 minutes of questioning. In the same paragraph he also wrote that by the end of the century the use of words and people’s ideas would have changed, so that one could without being contradicted.
The popular story:It tends to be said as a rule, like “fool 30% of the judges and you pass” The original source says:In the original paper it is not a rule for passing but his own expectation about about 50 years ahead. The numbers mean that an average interrogator will of making the right identification (that is, 3 out of 10 are wrong). Copeland’s 2000 paper (page 527) also gives examples of it being passed on the opposite way, as in .
What happened next:According to a survey paper from 2000 (Saygin et al.), no program had yet won the grand prize in the contest with prize money that had been held since 1991 (the Loebner Prize), and the records show that the machines were usually spotted quickly. In other words, in the year of the forecast, it had not come true in the form predicted. Some said the results of the 2000 contest , but in the same year, 2000, Copeland wrote that . Then in March 2025, researchers at a US university (UC San Diego) published in a paper (arXiv) the results of an experiment in which an interrogator chatted for 5 minutes with a human and a machine at the same time. Of two large language AIs told to play the part of a human, one (GPT-4.5) was judged to be the human 73% of the time and the other (LLaMa-3.1-405B) 56% of the time (since there were two choices, the interrogator correctly spotted the first one only in the remaining 27%). But this is the announcement of one research group, and we have not confirmed later evaluations on this site. The part about being able to has not been confirmed.
What we still don’t know:Whether a machine being judged human in the 2025 experiment means that it can is not known (Turing himself, regarding the original question as not worth discussing, replaced it with the game).
Turing tells radio listeners that come from a person or a machine
Turing gave a talk on BBC radio in Britain called . He said he thought a program that makes a machine think would be found someday, and forecast that by the end of the century it would be extremely difficult to tell whether the answers to questions came from a person or a machine. Right after, he added
What happened next:According to a survey paper from 2000 (Saygin et al.), no program had by then won the grand prize in the contest with prize money (the Loebner Prize), and machines were usually spotted quickly. In 2025, university researchers published a paper on an experiment in which, in a 5-minute conversation, a large language AI was judged to be human more often than the actual human (for details, see → Turing’s forecast: in about fifty years…).
In January 1952 on BBC radio, four people (Turing, the mathematician Newman, the neurosurgeon Jefferson and the philosopher Braithwaite) discussed . When Newman asked whether it would be , Turing answered
The popular story:People tend to say “Turing predicted that machines would pass the test around 2000” The original source says:On the radio in 1952 he himself answered for the form where any question is allowed (the in the 1950 paper was about a more modest condition: 5 minutes, an average interrogator, 70%).
What happened next:The target year has not come yet (awaiting the answer). In 2025 an experiment was published in a paper in which a large language AI was judged to be human at a high rate in the 5-minute conversation form (see → Turing’s forecast: in about fifty years…), but we have not confirmed results for the long form (a game played ) on this site.
What we still don’t know:We have not been able to view the broadcast script (AMT/B/6) itself on this site. We have not checked whether the recording survives.
On the radio in 1951, Turing said that if a machine can think, it might think more intelligently than we do. He said that even if we could keep the machines in a subordinate position, for example by switching off the power, the human race would feel greatly humbled. In a lecture script from the same period, he first said, , and then wrote that the machines would soon outstrip our feeble powers and that we must expect the machines to take control at some point.
The popular story:It tends to be cut out as “Turing predicted that AI would rule humans” The original source says:In the lecture script, this comes after the preface . In the radio script, too, he speaks conditionally, assuming that machines can think, and says the worry is .
What we still don’t know:Whether machines will become more intelligent than humans, and what would happen if they did, is still not known. The worry of 1951 is being discussed in the same form today, in the fourth boom (this record does not compare it with today’s debate).
Shannon’s forecast: machines that translate, arrange music and reason are
At the start of his chess paper, Shannon said that research on chess could be a stepping stone toward solving similar problems. As examples he listed eight, including machines that design circuits, translate languages, decide military operations, assign instruments to a melody, and carry out logical reasoning, and wrote that all of them seemed likely to come in the near future.
What happened next:A small-scale demonstration of a machine that translates languages was given in January 1954, four years later (→ IBM and Georgetown University give a pu…), but later research fell short of expectations for a long time (→ Dostert’s forecast: in 5 years, perhaps…). Music composed by a computer was performed in 1956 (the University of Illinois museum’s account). A logical reasoning program was built in 1955–56 (see the record of the Logic Theorist).
What the figure shows:Turing predicted that, about 50 years later, the chance of correctly identifying the machine would be no more than 70%. In 2025 experiments, the proportions of correct identifications were 27% and 44%.
201903–1956 · Japanese computers
Relays, vacuum tubes and phase
What kind of computers were being built in Japan at that time?
In 1952, the Electrotechnical Laboratory built a prototype of ETL Mark I, Japan's first digital automatic computer, using telephone-exchange relays. In March 1956, Bunji Okazaki of Fuji Photo Film completed, almost single-handedly, FUJIC, an electronic computer with about 1,700 vacuum tubes. It handled lens calculations about 2,000 times faster than calculating by hand.
In 1954, Eiichi Goto, a graduate student at the University of Tokyo, invented the parametron, a uniquely Japanese component. When a circuit of a coil and a capacitor is shaken at almost twice its resonant frequency, an oscillation starts, and its phase settles into one of two states, 0 or π. These stand for 0 and 1, and it was used as a majority-vote logic element. In the figure on the right, choose the three small inputs to start with, and let the oscillation grow. It settles into the phase of the majority.
x″ +ω²(1+h·sin 2ωt)x=0 (the shaking runs at 2ω)
x
oscillation of the circuit
ω
speed of the original oscillation
h
strength of the shaking
Other Japanese computers
In 1903, Ryoichi Yazu made and sold a gear-driven desktop calculator, the “Jidosanban” (automatic abacus). ETL Mark I was completely asynchronous, and was then described as running on a domino (shogi-daoshi) principle. In 1955 ETL Mark II, with 22,253 relays, was completed. At the University of Tokyo, the parametron computer PC-1 was completed in 1958.
In the world of stories, serialization of (Tetsuwan Atom) began in 1952.
Sources & confidence (5)Relays, vacuum tubes and phase
1952Verified in the originalJapan
The Electrotechnical Laboratory builds a prototype of Japan’s first automatic calculator, the ETL Mark I (relay type)
The national laboratory Denki Shikenjo (its name in 1976 was Denshi Gijutsu Sogo Kenkyujo, the Electrotechnical Laboratory) built a prototype of Japan’s first digital automatic calculator, the ETL Mark I, using relays (electromagnetic switches) from telephone exchanges. The circuits were designed with a theory of logical mathematics devised within the laboratory. Following this success, the ETL Mark II, a practical machine using more than 20,000 relays, was completed in 1955 and was used for about 10 years.
March 1956Confirmed in summariesSources disagreeJapan
Bunji Okazaki of Fuji Photo Film completes FUJIC, the first electronic computer to run in Japan
Designing lenses required calculating thousands of light paths. Bunji Okazaki of Fuji Photo Film got the idea of developing an electronic computer after reading an article in the 1948 magazine about IBM’s calculator SSEC. Working almost alone for 7 years, he built FUJIC, an electronic computer with about 1,700 vacuum tubes. He showed it running in November 1955 and completed it in March 1956. It did lens calculations about 2,000 times faster than calculating by hand.
3 sources and how they were checked
Where sources disagree:Start of assembly and construction: “assembly from March 1952” (the museum’s FUJIC page)/ “construction began in December 1952” (the same museum’s pioneer page).
Eiichi Goto, a graduate student at the University of Tokyo, invents the “Parametron”, a computing component unique to Japan
Eiichi Goto, a graduate student in Hidetoshi Takahashi’s laboratory at the University of Tokyo, invented a new component for expressing 0 and 1, the “Parametron”. It makes use of the fact that the oscillation of a circuit of a coil and a capacitor settles into one of two states (the phase is either 0 or 180 degrees). At the time, research and development of parametrons was also going on at Nippon Electronic Measuring Instruments, the Nippon Telegraph and Telephone Public Corporation, Kokusai Denshin Denwa, Hitachi, Fujitsu, NEC and others, and at the University of Tokyo the parametron computer PC-1 was completed in 1958.
January 1903Confirmed in summariesSources disagreeJapan
Ryoichi Yazu develops and sells Japan’s first mechanical desktop calculator, the “Jidosanban” (automatic abacus)
Ryoichi Yazu researched on his own and developed the “Jidosanban” (automatic abacus), a gear-driven calculator that takes in numbers using the same idea as the abacus. He obtained a patent in 1903 and put it on sale. With one cylinder and 22 gears it could add, subtract, multiply and divide. It was expensive at 250 yen per unit, but about 200 units were sold to government offices and others. During his research, Mori Ogai (Mori Rintaro, then head of the medical department of the 12th Division in Kokura) introduced him to a professor at Tokyo Imperial University and supported the development.
2 sources and how they were checked
Where sources disagree:Number sold: “over two hundred” (Information Processing Society of Japan)/ “about 200” (Japan Society of Mechanical Engineers).
Osamu Tezuka’s “Tetsuwan Atom” (Astro Boy) begins serialization; the birthday in the story is (translated)
Osamu Tezuka’s manga “Tetsuwan Atom” (Astro Boy) began serialization in the Kobunsha magazine . Atom is a boy robot with a heart, born from a supporting character in the earlier work (Ambassador Atom, 1951). The story begins on April 7, 2003, in the 21st century, when Dr. Tenma, the director of the Ministry of Science, builds a robot that looks just like his son who died in an accident. On the real April 7, 2003, there were events such as newspaper features and the handing out of extra editions as (translated) (announcement by Sony Pictures).
What we still don’t know:We could not confirm from the official site and Sony Pictures’ announcement in which work and which episode the date (translated) was first drawn (from the very start of the 1952 serialization, or in a later episode).
What the figure shows:Eiichi Goto's parametron used an oscillating circuit whose phase settled into 2 possibilities, 0 or π, and chose 0 or 1 by a majority vote of 3 inputs.
Closing
What this chapter still can't settle
What does it mean for a machine to produce something new (Lovelace's engine had ), and what does it mean to think? Lovelace in 1843, Jefferson in 1949 and Turing in 1950 argued about it, and it is still not settled. We also still do not know whether a machine being judged human in an experiment in 2025 means that it is thinking.
Some things also cannot yet be confirmed from sources: the manuscript of the 1952 radio discussion, the whereabouts of the original Gakutensoku, the episode where Atom's birthday was first drawn, how far the plans for Babbage's tic-tac-toe machine were actually built, and who first used the name .
What people of the time hoped for was machines that play chess, compose music and translate language (Poe 1836, Lovelace 1843, Shannon 1950). And the mechanisms in this chapter hold the seeds of the two later streams of AI: the stream that thinks with symbols and rules (Hobbes, Boole, Turing, Shannon) and the stream that learns with neural networks (McCulloch and Pitts, Hebb). In the next chapter, between 1955 and 1956, the name is born.