Effective Reasoning/Deduction and Induction

Deduction and induction are two different methods of reasoning.

• Deduction uses logical assumptions to reach a logical conclusion. It involves reasoning from one or more statements (premises) to reach a logical conclusion. In deductive logic, inference leads from a set of premises to a conclusion just as certain as the premises. If the premises are true, the conclusion cannot be false.
• Induction uses observations to justify a conclusion. In other words, inductive reasoning is drawing conclusions by going from specific to general. While deductive reasoning goes from general information to specific conclusion.

Inductive reasoning

Simple Definition: using observations to form a general conclusion.

Examples of Inductive Reasoning

Example #1	1) I see white swans on my walk every morning. 2) My friends say they've only seen white swans. 3) Therefore, all swans are white.
Example #2	1) Every time I have seen the sun rise, it has been in the east. 2) I have observed this pattern for several years. 3) Therefore, the sun always rises in the east.
Example #3	1) I drink coffee every morning. 2) Caffeine is addictive. 3) Coffee contains caffeine. 4) Therefore, I'm addicted to caffeine.

Deductive reasoning

Simple Definition: using logical premises to reach a logical conclusion.

If p represents all the premises, and q represents the conclusion then $p\Rightarrow q$. In other words, if all the premises are true, then the conclusion must also be true.