Do You Know How to Reason?

GMC’s Quality Enhancement Plan focuses on critical thinking. Part of that includes helping students learn how to use the five basic reasoning skills.  One of those is deductive reasoning.  We have all heard that term used before, but what is it? According to Dictionary.com, “Deductive reasoning is a logical process in which a conclusion drawn from a set of premises contains no more information than the premises taken collectively.” They use this example: “All dogs are animals; this is a dog; therefore, this is an animal.” Deduction begins with premises that are assumed to be true. If an untrue statement shows up at any point in the method, the conclusion becomes illogical and false. For example, if I said that all men are birds and this is a man; therefore, the man is a bird, I have reached an illogical and incorrect conclusion.  One must begin with accurate premises to begin the process of deductive reasoning. 

Another critical thinking skill is inductive reasoning. Put simply, inductive reasoning begins with data or evidence. The thinker then takes that data and evidence and arrives at a general conclusion based on that data.  According to scholars at Utah State University, an example of inductive reasoning would be:

“This cat is black. That cat is black. A third cat is black.  Therefore all cats are black.”  However, as one can see, this is an incorrect conclusion as the data is insufficient. Just like deductive reasoning, all points in the process must be solid and true, or in the case of inductive reason, sufficient. While the thinker here has surmised, based on his experience, that all cats are black, we know from a larger data collection (scientific evidence, the observations of other people who have seen cats of a different color) that this conclusion is wrong. However, the way we know that this conclusion is wrong is by examining data to reach a conclusion. 

A point to make here is that deduction and induction by themselves are inadequate to forward an defensible argument that is solid and will hold up under scrutiny.  As scholars at Utah State continue to point out, “While deduction gives absolute proof, it never makes contact with the real world, there is no place for observation or experimentation, no way to test the validity of the premises.  And while induction is driven by observation, it never approaches actual proof of a theory.”

To help further clarify the difference between the two, check out this video from the Khan Academy. 

https://www.khanacademy.org/math/precalculus/seq-induction/deductive-and-inductive-reasoning/v/deductive-reasoning-1

Try to learn these two reasoning methods and their dangers when used incorrectly to sharpen your thinking skills.

Dean Jeff Wells