Alan Turing

Start of the 20 th century The Atom Quantum physics Freud Philosophy …and a crisis in Maths!

Hilbert Believed maths could solve everything Came up with 23 unsolved problems in 1900 Thought about infinity

Hilbert 1930: “Wir müssen wissen. Wir werden wissen.”

Godel …but which ones are they?

Alan Turing – as a child Amazing scientist… …but bottom of class in English Messy Disorganised Watching the daisies grow

Early interests Plants and animals Chemistry experiments Quantum physics Philosophy Building machines

So… what did he prove? He had the idea that a mathematical proof is like a (computer) program that never gets stuck in a loop – it gets to an end and has an output.

Decision program (D) Can we write a program that can work out which programs are loopy? if loopy then output ‘LOOPY’ else output ‘OK’

Universal program (U) He designed a machine that can be fed any program and mimic it exactly… (using 0s and 1s)

What did he prove? That we’ll never know which theorems are provable and which aren’t… whilst also inventing the idea of computer programs and storing data!

WW2 - Station X Crossword and chess champions, mathematicians… and Alan Turing. No one knew who worked there and what anyone else was doing, not even husbands and wives!

Codes are quite important

Caesar’s cipher J MPWF NBUIT

The German Enigma machine The German Enigma machine was thought to be unbreakable… …some enigma machines had 1,800,000,000,000,000,000,000 possible combinations…

So how did they break it?

What affect did this have on the war? It gave information about where and how attacks would happen, especially from U-boats on Navy supply boats. It is believed to have shortened the war by 2 years… saving many lives!

After the war Built first chess playing machine Helped build first computer, the ‘Baby’

Building a brain What is intelligence? How do we learn? Can a machine think?

What is intelligence? …what do you think?

How would you teach a machine? Give it puzzles? Play games with it? Teach it to learn a language? Paint a masterpiece? Or would you just give it really good senses and ask it to work it out for itself somehow? Or…?

Can a machine think? What question would you ask? How might a computer ‘give itself away’? Is this a good test of intelligence?

Objections to Machine Intelligence Machines can only do what humans tell them They can’t write poetry They can’t appreciate strawberries They don’t have emotions like us… Religious reasons What do you think…?

Another amazing contribution! Around 1952, Alan got bored of answering the same old questions about humans and machines, so he went back to studying how things grow..

The end In 1954, he was found ‘guilty’ of having a homosexual relationship which was then illegal. He was put on probation if he took hormone therapy. He was found dead in his home in 1954 from Cyanide poisoning from an apple… was it suicide or one of his experiments gone wrong?

Snow white “Dip the apple in the brew, let the sleeping death seep through.”

2009: A public apology