WHEN TO MAKE A CHAIN

Hi Naty0405, thanks for the question! Conditional chains should be built whenever we have items/elements that are both sufficient in one statement and necessary in another. These are our linking points. Additionally, it is good practice to take the contrapositive of whichever conditional chain we have, simply to cover all conditions. In this case, we have the following structure: A -> B -> C The contrapositive of this will be: ~ C -> ~B -> ~A This is not a specific characteristic of Principle questions, however, you should always be on the lookout for conditional arguments, no matter which question type they are. In those cases where a question is purely conditional, diagramming both the original statement and its contrapositive is useful.

is a conditinal chain a contrapostive chain?

The contrapositive is just an equivalent way of diagramming the original conditional chain. There is no functional difference between the two.