TYPES OF REASONING Its elementary my dear class

TYPES OF REASONING It’s elementary my dear class

DEDUCTIVE REASONING • Referred to as “Top-down” reasoning • Deductive reasoning works from the more general to the more specific • Examines the possibilities to reach a specific, logical conclusion • Deductive reasoning usually follows steps. • A common form of deductive reasoning is the syllogism • Deductive inference conclusions are certain provided the premises are true

DEDUCTIVE EXAMPLE • All of our snowstorms come from the north. It's starting to snow. Therefore, the storm is coming from the north. • On a multiple choice test you have answers A, B, C, and D. If you know for sure that the answer is not A, B, or D. This means you can be sure that the answer is C, even if you don't actually have the knowledge to confirm it • Three witnesses saw John stab Jane. John has no twin brother. John had a reason to benefit from Jane's death. John's dna and fingerprints were found on the knife that was found a few feet away from Jane's corpse. John almost certainly killed Jane.

INDUCTIVE REASONING • Inductive reasoning makes broad generalizations from specific observations. • Conclusions are drawn from data and observations • Make many observations, discern a pattern, make a generalization, and infer an explanation or a theory • Bottom up form of logic – start specific, conclude with a generalization

INDUCTIVE EXAMPLES • The coin I pulled from the bag is a nickel. That coin is a nickel. A third coin from the bag is a nickel. Therefore, all the coins in the bag are nickels. • Bob is showing a big diamond ring to his friend Larry. Bob has told Larry that he is going to marry Joan. Bob has bought the diamond ring to give to Joan. • “Here is a gentleman of the medical type, but with the air of a military man. Clearly an army doctor, then. He has just come from the tropics, for his face is dark, and that is not the natural tint of his skin, for his wrists are fair. He has undergone hardship and sickness, as his haggard face says clearly. His left arm has been injured: He holds it in a stiff and unnatural manner. Where in the tropics could an English army doctor have seen much hardship and got his arm wounded? Clearly in Afghanistan. ” (Sherlock Holmes, Sherlock)