Scientific Method January 11, 2006

How do we know things? Tenacity Intuition Authority Rationalism Empiricism Science

Tenacity Habit or possibly superstition Example: “Only alcoholics can counsel other alcoholics” Exposure: The more we see something the more we like it Tenacity Make no guarantee of accuracy Has no mechanism for error correction

Intuition An approach that does not utilize inference or detailed reasoning No way of determining what is accurate vs. inaccurate Can be very helpful in suggesting an hypothesis But can be very misleading….

Authority Accepting knowledge because of respect for the source Some types of authority Government Parents Religion Employer No way to validate or question the knowledge Not the same as asking an expert – we can accept, reject, or challenge the statements of an expert.

Rationalism Knowledge through reasoning Logical deduction Assume knowledge is correct if correct process is used. Important for theory and pure math. Also logic puzzles like Sudoku Rationalism is useful to arrive at an hypothesis – then use scientific method to test hypothesis.

Example of Rationalism Premise: All dogs like chewing on bones Lassie is a dog Conclusion Therefore Lassie likes chewing on bones

Some Logical Fallacies Ad hominem (directed at the person) Ad antiquitatem (to tradition) Ad ignorantiam (to ignorance) Ad logicam (to logic) aka “straw man” Ad miscericordiam (appeal to pity) Ad populum (appeal to public) Ad numerum (appeal to numbers)

Some More Logical Fallacies Complex questions “Have you stopped beating your wife?” Cum hoc ergo propter hoc “With this, therefore because of this” Nearly identical to: post hoc ergo propter hoc After this, therefore because of this Mistakes correlation for causation Red herring Tu quoque “You too” Defending an error in one’s reasoning by pointing out the opponent made the same erro.

Empiricism Knowledge through experience “I have experienced thus it is true…”

Science Testing ideas empirically according to a specific set of procedures that is open to public inspection Based on objectively observed evidence Sans personal beliefs, perceptions, biases, attitudes or emotion

Scientific Method

Scientific Method Step 1: Observation Make an observation Most people in Florida with HIV/AIDS have financial difficulties. Inductive reasoning – based on observation, make a general statement People with HIV/AIDS have difficulty maintaining employment and medical benefits.

Scientific Method Step 2: Form an hypothesis Explain you observation Basically, this is your generalization from Step 1, but it may be more refined.

Scientific Method Step 3: Use hypothesis to generate a testable prediction Deductive reasoning: make a specific prediction based on your hypothesis Example: “When given a choice between two equally competent employees, one with HIV and the other without, most employers would hire the individual that is not HIV positive than the one who is HIV positive.”

Scientific Method Step 4: Design the study The most creative part Who are your participants Design: experimental, quasi-experimental, post-hoc, cross-sectional, longitudinal? This should be in part directed by the hypothesis or research question.

Scientific Method Step 5: Conduct the study Record what happens Make systematic observations

Scientific Method Step 6: Perform hypothesis testing Analyze you data with appropriate statistics Use the observations to support, refute, or refine your hypothesis. Example: “Employers in the skilled trades are less likely to hire an individual that is HIV positive versus employers of unskilled or professional workers.”

Scientific Method Science is empirical Science is public Science is objective

Scientific Method Being a scientist is not related to what you study… …only HOW you study it!