In day-to-day life we use logical reasoning, ofen wthout thinking "I can hear rain on the window and I'm about to go out, so I'll take an umbrella". Formal logics aim to make this explicit using mathematical notations and fixed sets of reasoning rules. Formal logic has been incredibly successful as a basis for mathematics and computing, but struggles to deal with more nuanced phenomena and uncertainty.
Used in Chap. 2: pages 14, 15