What is logic? Simply put, logic is about what is true and false, and how to reason about things. Informally, logic is also about “what is right and wrong” in a very machine-like manner. Logic can also be used to improve the way you think about learning.
To me, logic is more basic than mathematics. At its core, logic is about reasoning, both good and bad. For example, saying “anything is true” is ridiculous, because you can come with phrases such as “water is wet and water is not wet and water does not exist” which is obviously not true.
But can you, right now, reason and put forth why a statement does not make sense? Many people have trouble putting this “why” into words. Understanding logic, perhaps, will also make you able to understand why something is right and wrong according to some basic rules that you define. So, learning logic will make you better at checking yourself and your own logic.
I call this book “casual logic” because it is meant for “casuals” or people who are not dedicated to studying logic already. Many people don’t have enough time to slog through a book that assumes you know algebra. I expect readers to be at “ground zero.” Hopefully this book can turn you into somebody better than before.