Characteristics associated with informal logic are development of criteria, identification of logical fallacies, development of premises, criticism, argumentation tactics and analysis of data.
Informal logic is concerned with valid premise identification. A premise is the base which we build conclusions from. A premise is the main initial subject of a statement. Here is a statement:
“Because Henry has never told a lie, I believe him”
The premise here is “Henry has never told a lie”, our conclusion is believing Henry.
Development of Criteria
As we approach an argument, belief, or statement we must establish criteria for the premises. In the above example how might we look at the conclusion if we knew the premise was not true? What if we knew the premise was absolutely true? What if we did not not for sure either way? As you can see the validity of a premise is very important to be able to formulate true conclusions. To help us figure out if a premise is true or false we must be able to create criteria with which to judge them. Sometimes there will be many criterion or just one criteria.
To find out if a person has ever told a lie or not we might establish criteria such as:
- Asking the person questions with known answers to cross check
- Asking family and friends about the persons background and cross referencing those with facts or statements from the person
- Researching tapes and audio of the person and cross checking them against known facts
Also as we establish criteria for the premise these criteria should attempt to solidify logical absolutes about the condition of the premise.
Identifying Logical Fallacies
Logical fallacies are break downs and incorrect structuring of arguments and beliefs. Identifying logical fallacies is key to creating good arguments and beliefs. If something is structured fallaciously we cannot know if it is true or not because the logic of the statement is not sound. Remember though, that just because something is structured fallaciously does not mean it’s conclusion is false!
Informal Logic and Critical Thinking
A key skill that develops along with Informal Logic is critical thinking. This is often associated with informal logic because the practice of informal logic usually involves thinking about your own thoughts. When learning and practicing informal logic the logician should be as concerned with their own premises, possible fallacies, and logic structure as with the actual content of the discussion. In fact the content of the discussion is rather arbitrary until the logician can easily identify premises and logical fallacies. Identifying logical fallacies and premises naturally segues into critical thinking as we have to analyze how and why thoughts are formed.