It means that people studied hard to find natural ways to do things that seem like magic, using tools and technology. It's like the opposite of magic in some ways.

[That will have to be good enough, because the idea of actually defining what "science" is makes Kerry's head hurt.]

I don't have to help kidnappers.

[So there.]

People steal other people to work for them, you know. That's not helping, that's slavery. Even if they act nice, they shouldn't have brought us here when we don't want to be here. That's not nice.

[This kid needs to wise up for his own good, or he's going to get hurt.]

Why would they use fairy magic when they're not fairies? They probably have their own magic, or they use science.