How Do Machines Learn?

Once upon a time, we did things ourselves. Then we made software and told it what to do. Now we have software, called algorithms, that learn things on their own. They still need input, but what they learn from their input is much more than what we've programmed into them. Before we even realize, these machine programs know more than we do.  

CGP Grey makes sense of all this for those of us who don't program computers, much less design software or build artificial intelligence algorithms. Still, making machine smarter and smarter brings up more questions than it answers. First off, is that a wise thing to do? (via Metafilter)