The puzzle from last chapter is known as Hume's Problem of Induction.
Puzzle: If you observe 500 black ravens, what basis do you have for supposing that the next one you observe will also be black?
Many people's answer would be to apply Bayes's Theorem. For this to work, though, we need to make some assumption such as that all the ravens are drawn from the same distribution. If we don't assume that the future resembles the past at all, then it's very difficult to get anything done. This kind of problem has led to lots of philosophical arguments like the following.
Suppose you see a bunch of emeralds, all of which are green. This would seem to lend support to the hypothesis that all emeralds are green. But then, define the word grue to ...