How to Use Deductive Reasoning

Thinking hard

Deductive reasoning relates at least two general concepts or conditions to a specific case. For example, if a child is told that all fruit is sweet and is then given an apple, which the child identifies as a fruit, he or she will assume the apple will be sweet. Deductive reasoning relies on the assumption that the basic concept or condition that one begins with, in this example that fruit is sweet, is applicable in all cases. This allows the thinker to move from general ideas to specific instances, making connections along the way. Using this type of reasoning develops critical thinking skills.

Things You'll Need

• At least two general concepts or conditions assumed to be applicable in all cases
• Something you want to find out

Instructions

1. Determine exactly what you want to find out. For example, does Marty have his driver's license?

2. Gather all available information you have about the problem. This may include Marty's age (since he must be 16 to have a license), if he has taken driver's education (which he may not have passed), if you've seen him driving a vehicle (which he may be doing without a license), and if you know he is involved in anything that requires a license.

3. Find interrelationships between the pieces of information you've gathered. You know Marty is 16 because you asked his mom, who also told you he passed driver's education. Then you find out that he was just hired to deliver pizzas for Pizza Hut.

4. Move from the general to your specific case. Pizza Hut requires its delivery drivers to have valid drivers' licenses. Marty works for Pizza Hut as a delivery driver. Therefore, Marty probably has a valid driver's license.

5. Review your conclusion to make sure it is justified based on the information you have.

References

• Use Deductive Reasoning
• Deductive Reasoning
• Deductive Reasoning Definition