Induction and Deduction

1. Induction and Deduction

2. Inductive Reasoning • Induction is the process of drawing a general conclusion from incomplete evidence. • You consider evidence you have seen or heard to draw a conclusion about things you haven’t seen or heard • The intellectual movement from limited facts (a sample) to a general conviction is called an inductive leap

3. Inductive reasoning cont’d • For a claim to be credible the sample must be: 1.Known 2.Suffiecient 3. representative

4. Is the sample known?

5. Is the sample sufficient?

6. Is the sample representative?

7. Occam’s Razor • Occam’s Razor: the maxim that when a body of evidence exists, the simplest conclusion that expresses all of it is probably the best. • Maxim: 1. a general truth, fundamental principle, or rule of conduct

8. Deduction

9. Deduction • Opposite of induction • Deduction moves from a general truth to a specific example • Vehicle of deduction is the syllogism

10. Syllogism • This is an argument that takes 2 existing truths(premise) and puts them together to create a new truth • Classic Example: • MAJOR PREMISE: All men are mortal • MINOR PREMISE: Socrates is a man • CONCLUSION: Socrates is mortal

11. Conditions of a Reliable deductive argument • The premises must be true • The terms must be unambiguous • The syllogistic form must be valid

12. Major and Minor premises • Premises in a syllogism must be true • Major premise is derived from induction • Minor premise is derived from using the 5 senses (taste, touch, hear, smell, see)

13. Syllogism language • The terms of a deductive argument must be clear and consistent • If definitions change within a syllogism, arguments can become fallacious