11.1 MAPPING REASONS AND OBJECTIONS
Arguments in real life are often very complicated. A discussion might involve multiple arguments. A set of premises can have multiple conclusions, or it might be unclear which are the premises and conclusions. In these situations, diagrams known as argument maps can display the logical structure of arguments more clearly. In an argument map, arrows link premises to their conclusions. Here is a simple one with only one premise and one conclusion:
The world is getting warmer.
Winter will be shorter in many countries.
When we use an arrow to link from a sentence P to another sentence Q, this indicates that P is a reason for accepting Q—that is, P gives an answer to the question “Why believe Q?” So the following map is wrong:
It should be like this instead—two premises leading to a single conclusion:
The following map has a single premise with multiple conclusions:
Of course, you might not need to draw diagrams for simple arguments. The power of argument maps comes in when we are dealing with more complicated ...