The Venn diagram got its name from philosopher, mathematician, developer of logic and
probability theory, John Venn. The diagram has many purposes which vary depending on what is
being compared. To understand how a Venn diagram works, one must break it down to smaller
pieces. A class, often referred to as a set is a collection of objects and is represented by one circle
of the diagram. The individual objects are called members of the set. When you have a typical
Venn diagram which consists of two intersecting circles you really are working with four
different regions. The area outside the circles is one (a class that does not contain any properties
of the two circle classes), one circle is two (which represents a property that the other circle does
not have), the intersecting area between the circles is three (common properties between the two
circles), and the second circle is four (again, representing a property that the other circle does not
have. There are also Venn diagrams that consist of three circles and eight regions. The idea is the
same in that areas which overlap represent commonalities between the circles. Shading in Venn
diagrams is representative of something that is not in existence, while ticking represents
something that actually does exist. A Venn diagram is very similar to a math equation in that in
contains similar properties. The properties are as follows:
1) “The argument has two premises and a conclusion.
2) The argument mentions at most three classes of objects.
3) The premises and the conclusion include only statements of the following form: Every X
is Y, Some X is Y, No X is Y.”