Logic:The art of non-contradictory identification.
Logic is a process that partially consists of detecting contradictions in ideas. When we find a contradiction, we identify that something is wrong and we can search for a mistake.
Logic can also lead to new knowledge by showing what must be true in order to avoid a contradiction. Logical syllogisms are methods of taking a number of premises and showing that when they are all taken as true, they lead to a necessary conclusion.
A classical example says that "All men are mortal" and that "Socrates is a man". When combined, these two statements must lead to the conclusion that "Socrates is mortal". If that conclusion were rejected, it would create a contradiction.