Inference to the Best Explanation

One of the most common inferences in life is the inference to the best explanation (sometimes called abductive reasoning). We use this type of reasoning to infer what would best explain the things that we see. Chapter 6 in our book demonstrates ways in which this type of reasoning helps us to explain the world around us.

Prepare: To prepare for this lesson take a close look at the sections from Chapter 6 on "Inference to the Best Explanation," "Form," "Virtue of Simplicity," and "How to Assess an Explanation." Choose a topic that is difficult or controversial to explain. Some good topics include hoaxes, unusual sightings (e.g. UFOs, bigfoot, the Loch Ness monster), the supernatural or paranormal, events that are the subject of conspiracy theories, unsolved crimes or other court cases, etc.

Reflect: Do a little research to find a specific topic and learn about explanations on both sides. Consider what you think might best explain the observed facts of the case.

Write: Explain the topic you chose and why it is interesting or controversial. Present good arguments on more than one side of the issue (e.g. competing explanations of the facts). Analyze both arguments that you have presented. Then present your own argument for your theory that you feel will best explain this phenomenon. Are there any holes in your theory? Is there any information that would be likely to strengthen or weaken your case?

Example Below

Argument 1:

Premise 1: Marijuana and prescription drugs can be an addictive substance.

Premise 2: Marijuana is illegal in most states.

Premise 3: Marijuana is not as addictive as some prescription drugs.

Premise 4: Having prescription drugs products is not illegal.

Conclusion: In states where the possession of marijuana is illegal the government should not enforce any penalties for having it.

The validity of this argument is true only if the premises of marijuana and prescription drugs are proven facts. If you can show that marijuana has a higher addiction rate than prescription drugs, it should be illegal in all states.

Argument 2:

Premise 1: Blue is a primary color

Premise 2: Yellow is a primary color

Premise 3: Red is a primary color

Conclusion: Since Blue, Yellow and Red are primary colors, all other colors come from them.

This conclusion of this argument is valid only if you are able to strip all colors down to their base color to verify at least two of the primary colors were used to create the different shades of the other colors.