Can you tell the difference between AI and a human? | Michael Wooldridge | Big Think

• The limits to computing are not the limits of physical devices. They're not the limits of concrete or steel or anything like that in the physical world; the limits to computing are the limits of your imagination.

When the first computers began to appear in the late 1940s and early 1950s, people were fascinated by these incredibly complex machines that could do things like process huge numbers of mathematical equations incredibly quickly. And so there was a buzz at the time around these electronic brains, with lots of people thinking, "Can machines really be intelligent?"

So Alan Turing, I think, was one of the most remarkable people of the 20th century. What he did was invent a beautiful test. He said, "Look, here is this test. If we ever get something that passes it, then just stop asking that question because you can't tell the difference." He never really expected that anybody was seriously going to try it out, but actually people did try it out. However, it's been wildly misinterpreted, I say since then.

What Turing's most famous for is working at Bletchley Park, a code-breaking center in the United Kingdom throughout the Second World War. And actually, if that was the only thing he'd done in his life, he would have a place in the history books. But almost as a side product of his PhD work, he invented computers, which are just one of the most remarkable quirks of history.

With incredible precociousness, he picked one of the biggest mathematical problems of the age, the Entscheidungsproblem, which means decision problem; whether mathematics can be reduced to following a recipe. The question that Turing asked was whether it is the case that for any mathematical problem that you might come up with, you can find a recipe which you can just follow in the same way that you would follow for arithmetic.

Incredibly quickly, within about 18 months, Turing solved it. And the answer is no; mathematics doesn't reduce to following a recipe. The interesting thing is that in solving that problem, he had to invent a machine which could follow instructions, and nowadays we call them Turing machines, but actually, they are basically modern computers.

He was one of the first serious thinkers about AI. In 1950, he published what we think is the first real scientific work around artificial intelligence. If we ever achieve the ultimate dream of AI, which I call the Hollywood dream of AI—the kind of thing that we see in Hollywood movies—then we will have created machines that are conscious, potentially in the same way that human beings are.

So Alan Turing, I think, was really frustrated by people saying, "Well, no, of course these machines can't be intelligent or creative or think or reason," and so on. Turing's genius was that he invented a beautiful test, which we now call the Turing Test in his honor.

Okay, so here's how the test goes. You've got somebody like me, who's sitting at a computer terminal with a keyboard and a screen, and I'm allowed to ask questions. I type out questions on the keyboard, but I don't know what's on the other end, right? I don't know whether it's a computer program or another human being.

So Turing's genius was this: He said, "Well, look, imagine after a reasonable amount of time, you just can't tell whether it's a person or a machine on the other end. If a machine can fool you into not being able to tell that it's a machine, then stop arguing about whether it's really intelligent because it's doing something indistinguishable. You can't tell the difference. So you may as well accept that it's doing something which is intelligent."

I think Turing never really expected that people would seriously try it out. There are annual Turing Test competitions across the world where people will enter computer programs, and there will be judges who will try to tell whether they're a computer program or a human being. Most of the entries in them are like these kind of crude internet chatbots. What these chatbots do is they just look for keywords like "sad" or "fami..."