Retailing has gone from an information-scarce to an information-rich environment.

In the global millennium goals, we're on track to beat and eliminate severe poverty. So there are lots of positive trends. I think the world in 25 years could be a much better version of the world we have today. But the role of humans would still be fundamentally at the center of that.

But the broader lesson of the first Industrial Revolution is more like the Indy 500 than John Henry: economic progress comes from constant innovation in which people race with machines. Human and machine collaborate together in a race to produce more, to capture markets, and to beat other teams of humans and machines.

Going a little further into the future, we'll start literally connecting to machines. Some of my colleagues at MIT here - some of them are working on a neural mesh that connects directly to your brain, and they've already done it with some disabled people and allowed them to move objects just by thinking.

Machines already are much smarter than us at so many things. I mean, try to multiply two 10-digit numbers with each other or, you know, sift through a thousand documents. So there's lots of things that machines are better at including in mental task than us. There's many more that they're not as good at, but the direction is pretty obvious and the progress is clear.

Now comes the second machine age. Computers and other digital advances are doing for mental power - the ability to use our brains to understand and shape our environments-what the steam engine and its descendants did for muscle power.

Computers get better, faster than anything else ever. A child's PlayStation today is more powerful than a military supercomputer from 1996. But our brains are wired for a linear world. As a result, exponential trends take us by surprise. I used to teach my students that there are some things, you know, computers just aren't good at like driving a car through traffic.