When I read philosophy or neuroscience papers about consciousness, I don't get the sense we're any closer to understanding it than we were 50 years ago.

We call ourselves Homo sapiens--man the wise--because our intelligence is so important to us. For thousands of years, we have tried to understand how we think: that is, how a mere handful of matter can perceive, understand, predict, and manipulate a world far larger and more complicated than itself. The field of artificial intelligence, or AI, goes further still: it attempts not just to understand but also to build intelligent entities.

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.

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.

When I read philosophy or neuroscience papers about consciousness, I don't get the sense we're any closer to understanding it than we were 50 years ago.

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.

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