Leg locomotion was, for decades, thought to be an incredibly difficult problem. There has been very, very painstakingly slow progress there, and robots that essentially lumbered along at one step every 15 seconds and occasionally fell over.

Some PhD physicists write software or work for hedge funds, but physics still has a problem with having very smart people but not enough opportunities.

AI's ability to recognize visual categories and images is now pretty close to what human beings can manage, and probably better than a lot of people's, actually. AI can have more knowledge of detailed categories, like animals and so on.

You're able to use a search engine, like Google or Bing or whatever. But those engines don't understand anything about pages that they give you; they essentially index the pages based on the words that you're searching, and then they intersect that with the words in your query, and they use some tricks to figure out which pages are more important than others. But they don't understand anything.

The robot is not going to want to be switched off because you've given it a goal to achieve and being switched off is a way of failing - so it will do its best not to be switched off. That's a story that isn't made clear in most movies but it I think is a real issue.

Its really important to understand the difference between sentience and consciousness, which are important for human beings.

What AI could do is essentially be a power tool that magnifies human intelligence and gives us the ability to move our civilization forward. It might be curing disease, it might be eliminating poverty. Certainly it should include preventing environmental catastrophe. If AI could be instrumental to all those things, then I would feel it was worthwhile.