Understanding "understanding"

I have lately been wondering about how we understand things. How we capture data from different sources and relate to each other to make it meaningful. Being a programmer, I wish that these can help make computers understand. Now all that we do is make it work the specifically the way we want them to work. A simple google search would reveal that "Machine learning" is the way to go. But first do we understand how we understand?

I ponder about these and hope to post what I think about.

Note: I have used a link to the Andrew's lecture notes. It is only to indicate a reference to the topic.