Types of Reasoning

1. Types of Reasoning Deductive vs. Inductive Arguments

2. Start with Observation • A good scientist / investigator is observant. • Gaining knowledge from observations is cumulative. • For years, people based their beliefs on their interpretations of what they saw going on in the world with around them without testing the ideas to determine validity… not scientifically valid.

3. From Observations to Theory • Need reasoning and logic to mold your observations into an acceptable theory. • Valid reason flow will take you from through the process. • Two major types of reasoning arguments we will discuss – deductive and inductive

4. Deductive Arguments • Arguments that claim to provide complete support for the conclusion. • Arguments whose claim is that if the premises are true, the conclusion must be true • Impossible to have true premises and false conclusions at the same time. • These are the arguments that will ‘make your case’. • Logically valid

5. Inductive Arguments • Arguments that claim to provide some, but not complete, support for the conclusion. • No matter how strong the argument, it is always possible for the conclusion to be false even though the premises are true. • Not logically valid • Can play part in discovery of truths.

6. Summary • Inductive reasoning is part of the discovery process whereby the observation of special cases leads one to suspect very strongly that some general principle is true • Deductive reasoning is the method you would use to demonstrate with logical certainly that the principle is true • Both are used in a most investigations