I just want to reiterate this point about how knowledge, factual knowledge, is acquired. If you ever looked up a word in the dictionary, and then you come across the word six weeks later, and you have no idea what it means. We don't learnt what a word means by looking up in the dictionary. We learned about it from hearing it a number of times in context, in conversation and reading. This whole idea that you can just sort of looked up stuff on wickapedia when you need it, or google it, is valuable for certain things. But it doesn't go into the brain. It's not obvious to me, and i suspect there's science behind this,