Science as a Way of knowing & Developing and Testing Hypotheses

1. ISB 202, Section 005 Science as a Way of knowing & Developing and Testing Hypotheses

2. What is Science? Scientific method(s) & other ‘ways of knowing’

3. So, how do we come to “know stuff”, anyway ?

4. Four basic ways that we may come to decide that something is “true”….

5. Four basic ways that we may come to decide that something is “true”: 1) We have relevant personal experience on the topic

6. Four basic ways that we may come to decide that something is “true”: 2) We trust the source of the information

7. Four basic ways that we may come to decide that something is “true”: 3) We have a sense of intuition or inspiration about it

8. Four basic ways that we may come to decide that something is “true”: 4) We reach a tentative conclusion of an explanation, and seek ways to make skeptical tests of that ‘hypothesis’

9. Four Basic Ways of Knowing Method of: EXPERIENCE AUTHORITY INTUITION SCIENCE • We have relevant personal experience on the topic • We trust the source of the information 3) We have a sense of intuition or inspiration about it 4) We undertake skeptical investigation of ‘hypotheses’

10. Each of these ways of knowing is potentially flawed. "Smart people can come up with very good explanations for mistaken points of view." People have argued issues of all kinds for centuries, but arguments cannot determine whether a statement is correct.

11. Each of these ways of knowing is potentially flawed. Method of: EXPERIENCE Optical illusions!

12. Each of these ways of knowing is potentially flawed. “The Moon Illusion” Method of: EXPERIENCE

13. Each of these ways of knowing is potentially flawed. John Needham (1748) Mice generate spontaneously from garbage Method of: EXPERIENCE AUTHORITY Aristotle: Sun rotates around the earth

14. Each of these ways of knowing is potentially flawed. 45 FAILED END-OF-THE-WORLD PREDICTIONS FOR 1999 http://www.religioustolerance.org/end_wrl9.htm Galileo and Heliocentrism, 1633 Salem Witch Trials, 1692 Method of: EXPERIENCE AUTHORITY INTUITION

15. Each of these ways of knowing is potentially flawed. Scientific findings are refuted, or refined, continuously. This is how science progresses. Method of: EXPERIENCE AUTHORITY INTUITION SCIENCE Newtonian Physics vs. Relativity

16. Each of these ways of knowing is potentially flawed. …but science emphasizes the need to be self-correcting. Hypotheses as “a working model” of reality

17. …but science emphasizes the need to be self-correcting. Be skeptical, devise tests of hypotheses; continually seek out exceptions to ‘rules’, and so on ….

18. Advantages to the Scientific Method • A major attempt to be: • Unprejudiced (unbiased - but this is not always the case b/c scientists are people) • Repeatable • Falsifiable

19. Developing & Testing Hypotheses Science is a way of knowing that tries to get closer and closer to the truth by chipping away at what’s false.

20. Developing and Testing Hypotheses Types of Questions • Proximate • “how”, “where”, “when”, “who”, “what” questions • largely answerable • Ultimate • “why” questions • largely unanswerable ? ? ? ? ? ? ? ? ? ?

21. Developing and Testing Hypotheses Types of Questions Proximate How do mountains form? What causes lung cancer? How do clouds form? Where does rainwater end up? Ultimate Why are we here? Is Michigan’s UP beautiful? What is considered cruel? Was the course of evolution directed by a supernatural being?

22. Developing and Testing Hypotheses Types of Questions • Proximate • often can be tested by the scientific method • Ultimate • usually not able to be tested by the scientific method ? ? ? ? ? ? ? ? ? ?

23. Two Views of How Science is Done • Scientists themselves: • - Testing hypotheses • Creative thinking • General public: • Collecting ‘facts’ • Unbiased, dispassionate

24. What is a hypothesis? • idea or proposition that can be tested by observations or experiments about the natural world • hypotheses are subject to scientific evaluation and must be falsifiable. • A hypothesis can never be proven. It can be CONFIRMED (supported) or it can be FALSIFIED (rejected).

25. Null Hypothesis (Ho): Observation • hypothesis to be tested • anticipates no effect or difference between/among test groups Question Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential Hypotheses Pop. A Pop. B Pop. C Ho: wing length does not differ among dragonfly populations

26. Alternative Hypothesis(es) (HA): Observation • hypothesis to be tested after null hypothesis is rejected • must predict the difference between/among test groups Question Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential Hypotheses Pop. A Pop. B Pop. C HA: wing length in dragonfly population A is greater than that of populations B and C

27. Observation Reject Hypotheses 1 & 4 Question Reject Hypotheses 2 & 3 Experiment Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Experiment Hypothesis 2 Hypothesis 3 Hypothesis 5 Potential Hypotheses Hypothesis 5 Remaining Potential Hypotheses Predictions Experiment 3 Experiment 1 Experiment 2 Experiment 4 Predictions Confirmed

28. Scientific Theories and Laws • Scientific data • Natural laws • Experiments • Scientific hypotheses • Scientific models • Scientific theories Fig. 2-2

29. What is a scientific theory? earliest reptile • Examples: • Theory of evolution • Theory of relativity earliest bird http://sci.waikato.ac.nz/evolution/Theories.shtml http://www.besse.at/ sms/evolutn.html earliest mammal • A scientifictheory is a coherent explanation for a large number of facts and observations about the natural world. •  Internally consistent and compatible with the evidence (patterns in data!) •  Firmly grounded in and based upon evidence • Tested against a wide range of phenomena • Demonstrably effective in problem-solving

30. Examples: • Laws of thermodynamics • Mendelian laws of heredity • Law of gravity http://sci.waikato.ac.nz/evolution/Theories.shtml What is a scientific or natural law? A Scientific or Natural Law is a description of a natural phenomenon or principle that invariably holds true under specific conditions and will occur under certain circumstances.