I'm Rory Stewart and I grew up wanting to be a hero and I'm still fascinated by the ideas of heroism.

In my new series, I'm taking in the long sweep of history from Achilles to Zelensky and asking, what is a hero?

Simply doing your job, being a decent human being.

A true hero is someone who just kind of shines

by their own light and that light is to be recognised by others. The long history of heroism

with me, Rory Stewart. Listen on BBC Sounds. Thanks for downloading the In Our Time podcast.

For more details about In Our Time and for our terms of use, please go to

BBC.co.com.uk forward slash radio four. I hope you enjoy the program. Hello. Can machines think?

It was the question posed by the mathematicians at Bletchley Park, and especially by the codebreaker,

Alan Turing. And it's a question that's still being asked today.

What's the difference between men and machines, and what does it mean to be human?

And if you can answer that question, is it possible to build a computer that can imitate the human mind?

In 1949, the eminent neurosurgeon, Professor Jeffrey Jefferson,

argued that the mechanical mind could never

rival a human intelligence because it could never be conscious of what it did.

He said, not until a machine can write a sonnet or compose a concerto, because of thoughts and

emotions felt, and not by the chance fall of symbols, could you agree that the machine

equals brain, that is, not only write it, but know that it's written it.

Yet the quest rolls on for machines that are bigger and better at processing symbols

and calculating infinite permutations.

Who were the early pioneers of artificial intelligence and what drove them to imitate the operations

of the human mind?

...