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  • The history of computer science is heckin' cool.

  • It features the upending of basic questions, likewhat is information?

  • It has biographical oomphonly this story's war-hero scientist, Alan Turing, was punished,

  • not celebrated, after helping the Allies win World War Two.

  • And the history of computer science raises profound questions about technology and society,

  • likehow do we know that our big complex beautiful brains aren't really just big

  • complexcomputing machines?

  • And, if we can one day build machines that think as fast as humans, will we have to grant

  • them human rights?

  • [INTRO MUSIC PLAYS]

  • Questions about thinking machines are relatively recent in history.

  • But all kinds of doing machines are not, and some of this doing involves solving mathematical

  • problems and other high-level functions.

  • Some time before 60 BCE, the Greeks constructed an analog computer now called the Antikythera

  • mechanism.

  • Using many gears, the mechanism may have been used to predict eclipses or other astronomical

  • events.

  • But the mechanism appears to have been a one-off.

  • So historians often give credit for the first mechanical computer to the Artuqid-Turkmen

  • engineer, Al-Jazarī, who died in CE 1206.

  • We met him way back in episode seven when dude built a robotic musical band.

  • And a robot toilet helper!

  • And Al-Jazarī built an astronomical clock that showed the signs of the zodiac and could

  • be reprogrammed to compensate for changing lengths of the day.

  • Then, in 1642, French mathematician Blaise Pascal invented a mechanical adding machine

  • that used a collection of rotating numbered wheels, similar to a car's odometer.

  • Our friend from episode seventeen, German mathematician Gottfried Leibniz, built commercial

  • mechanical calculators in the late 1600s.

  • And in 1801, in the early days of the Industrial Revolution, French merchant Joseph Marie Jacquard

  • incorporated the punch card into a textile loom to control patternsarguably the first

  • industrial use of computing!

  • But devices like calculators and looms are pretty far from the computers we rely on today.

  • So then the question becomes, like... what is a computer?

  • Well, that word has changed a lot over the years.

  • In fact, up until the 1950s, a “computerwas a person who computesusually a woman.

  • The basic idea today is that a “computeris a machine that can be programmed to perform

  • logical taskslike math problemsautomatically.

  • For many historians, the dream of a somewhat recognizable modern computer that can be programmed

  • to perform all sorts of calculations without continuous human number-punching, dates back

  • to 1837.

  • That's when British mathematician Charles Babbage fully conceived a digital, programmablebut

  • mechanicalcomputer called the difference engine.

  • This was a general purpose information processor: it wasn't just for a single task, but for

  • solving general logic problems.

  • Sadly, the difference engine was never completed.

  • Babbage started working on it, but never finished due to cost overruns and fights with his machinist.

  • But we have his notes and those of his chronicler, British mathematician Ada Lovelace, who wrote

  • the first algorithm intended for processing using a computerbasically, the first computer

  • program!—in 1843.

  • Fun fact, Lovelace was the daughter of Romantic poet Lord Byron!

  • Another early computer was actually made and put into use in the United States.

  • A young mathematicianinventor named Herman Hollerith combined the old technology of punch

  • cards with the new technology of electrical circuits to produce a sorting and tabulating

  • machine.

  • With his machine, the 1890 census was finished in weeks instead of years.

  • Hollerith went on to found the Tabulating Machine Company.

  • And it's still in business todayas the International Business Machines Corporation,

  • or IBM.

  • But neither Babbage and Lovelace's way-ahead-of-their-time designs nor Hollerith's super-sorter established

  • computing as a science.

  • Some important developments happened in the years before World War Two.

  • For example, starting in the late 1920s, influential American engineer Vannevar Bush created an

  • analog computer called a differential analyzer, which could solve calculus problems with as

  • many as eighteen independent variables.

  • But the war shoved computer science into the scientific limelight.

  • In the 1930s, British mathematician, linguist, cryptographer, philosopher, and all-around

  • smarty pants Alan Turing laid the foundation for a mathematical science of computing.

  • ThoughtBubble, introduce us:

  • Turing proposed the aptly named Turing machine—a thought experiment to figure out the limitations

  • of mechanical computation.

  • A Turing machine can theoretically perform an algorithm, or programmed operation.

  • It's a universal computer.

  • Turing couldn't make an abstract perfect computer, but he could lay out how the logic

  • of writing and reading programs should work, and how a relatively simple device could,

  • given enough memory, accomplish any logical operation.

  • During the war, Turing went to work in the super-secretUltraprogram at Bletchley

  • Park, which was an estate for British codebreakers.

  • Turing wasn't the only computer innovator at Bletchley.

  • For one thing, eight thousand women worked there!

  • Also, an engineer named Tommy Flowers designed some for-the-time hyper-advanced computers

  • called the Colossus series, which also helped the Allies a lot.

  • And were kept secret until the 1970s!

  • But Turing's job, leading Ultra Hut Number Eight, was to decipher encrypted messages

  • about German naval movements.

  • The Germans used a device called an Enigma machine to create supposedly unbreakable ciphers,

  • or ways of encoding messages so that only someone with the same cipher could read the

  • message.

  • But Turing broke through, using a computer he built called the bombe, based on a Polish

  • computer.

  • These wartime computers weren't super fast or sophisticated.

  • They were smart ways of automating a lot of dumb tasks.

  • Thanks ThoughtBubble

  • After the war, Turing kept working on computers.

  • His 1948 essayIntelligent Machinerygave more details on the Turing machine.

  • Then, in 1950, he publishedComputing Machinery and Intelligencein the journal Mind.

  • Go read it, it holds up!

  • Basically, this article became foundational text in artificial intelligence or AI.

  • Turing famously stated that the appearance of intelligence is proof of it.

  • Turing arrived at this idea by thinking about a limit case: consider a computer that appears

  • truly intelligent, like a human.

  • How would we know whether or not it is intelligent?

  • Turing proposed a game to test the computer: talk to it like a person!

  • This game is called the Turing Test and is still used as a challenge in AI:

  • a human asks questions to both a computer and another human, through a terminal, and

  • tries to guess which is which from their responses.

  • The Turing Test was based on an old party game, in which you did the same thing via

  • written notes, and tried to guess which of two unknown people was a man and which

  • a woman.

  • The Turing Test led to the ChurchTuring Hypothesis: computation power is computation

  • power.

  • It doesn't matter if that power comes from electrical circuitry or a human brain, or

  • how fast the individual parts of the machine are.

  • So any machine of sufficient power should be able to do any computation that a brain

  • can do.

  • So… a sufficiently complex machine would be as intelligent as a brainor more.

  • The only limit to computational power is memory.

  • But in real life, no computerwhether brain or series of electrical circuitshas infinite

  • memory.

  • Even more ahead of his time, in his 1950 paper, Turing suggested thatinstead of trying

  • to straight-up build a computer as intelligent as an adult humanit would be smarter to

  • build a child's mind and then teach it how to learn on its own.

  • BAM, machine learning!

  • So what recognition did Turing get for all of his hard work?

  • In 1952, in the course of a police investigation of a burglary at his home,

  • the officials became aware that he was in a relationship with another man, and the British

  • government pressed charges.

  • Turing was convicted ofgross indecencyand sentenced to take libido-lowering hormones.

  • He died in 1954, possibly of suicide by cyanide-poisoned apple, possibly by inhalation of cyanide while

  • working.

  • Either way, one of the greatest minds to ever live died at age forty-one.

  • He was not pardoned until 2016.

  • But before Turing died, he met with some important folks in the United States

  • Hungarian-American physicist John von Neumann

  • met Turing in the 1930s and worked on foundational aspects of computer

  • science and AI.

  • Von Neumann proposed the idea of storing a computer program in the computer's memory.

  • So instructions could be stored externally, instead of having to be fixed permanently

  • in a given machine.

  • Turing also met with American mathematician named Claude Shannon during the 1930s, sharing

  • his ideas about the Turing Machine.

  • Shannon, who invented the wordbitand founded digital computing and circuit design

  • theory while still a graduate student at MIT.

  • And conducted some Turing-like codebreaking during World War Two.

  • But he's most well known for publishing a series of papers after the war that founded

  • information theory, which examines how information is encoded, stored, and communicated.

  • We could do a whole episode on information theory, but some of the effects of Shannon's

  • work were to help transition computers, televisions, and other systems of moving around information

  • from analog to digital.

  • And information theory led to the Internet!

  • And over at Harvard, American physicist Howard Aiken worked with the military and IBM to

  • design and build a computer, the Harvard Mark I, in 1944.

  • This device was used by von Neumann to run a program to help design the atomic bomb.

  • One of the other first programmers of the Mark I was American computer scientist and

  • rear admiral Grace Hopper,

  • who invented one of the first compiler tools to translate programming language into machine

  • code.

  • She then worked on machine-independent programming languages, developing the early programming

  • language COBOL.

  • Computers after World War Two quickly became bigger, faster, and more complexlike the

  • U.S. Navy-sponsored Electronic Numerical Integrator and Computer, or ENIAC, 1946,

  • which filled up a large room, and UNIVAC in 1951, which was commercially mass-produced.

  • These general-purpose computers were based on the principles laid out by theorists like

  • Turing, von Neumann, and Shannon, and they used the languages developed by programmers

  • like Hopper.

  • These computers were built using a digital codebinary, with values of onlyone

  • orzero”.

  • And real-world computing really took off after the invention in 1947 of the solid-state transistor

  • by William Shockley at Bell Laboratories and room-fillingmainframecomputers for

  • businesses.

  • In a later episode, we'll get to back to computersand introduce one of our very

  • best friends in the history of technology, the Internet.

  • But for now, let's remember that, up until the 1950s, a computer was a person, usually

  • a woman, who was a number cruncher

  • that is, someone who computes, using a machine.

  • One of thosecomputerswho became an engineer who used a computer was African-American

  • rocket scientist Annie Easley.

  • In the era of Jim Crow laws, Easley left Alabama and went to work for NASA in Ohio.

  • She developed computer code for NASA missions for decades.

  • Thus next timehumans finally get to play golf on the moon.

  • It's the birth of air and space travel!

  • Crash Course History of Science is filmed in the Dr. Cheryl C. Kinney studio in Missoula,

  • Montana and it's made with the help of all this nice people

  • and our animation team is Thought Cafe.

  • Crash Course is a Complexly production.

  • If you wanna keep imagining the world complexly with us, you can check out some of our other

  • channels like Scishow, Eons, and Sexplanations.

  • And, if you'd like to keep Crash Course free for everybody, forever, you can support

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  • a crowdfunding platform that allows you to support the content you love.

  • Thank you to all of our patrons for making Crash Course possible with their continued

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The history of computer science is heckin' cool.

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