Checking for validity with diagrams

Chapter eight discusses how to check validity with diagrams. There are several steps on checking whether an argument is valid. The checks that a diagram must go through are that a collection must be an enclosed area, one premise is entirely related and within another, if there are comparisons to on another then there are similarities that each share, if the two areas do not overlap than there is nothing in common, an a or dot represents that the object is in that collection, and making sure that the argument is valid by checking that there is no way the premises are true and the conclusion false. These checks basically give evidence to an argument by using diagrams. An example given in the book is that all animals that bark are mammals. All dogs bark. Therefore all dogs are mammals. There is no way that a dog could not be mammal because dogs are within things that bark and are mammals.