What is Science?

Science: [scientia, knowledge] Knowledge gained through experience… Accumulated and accepted knowledge that has been systematized and formulated with reference to the discovery of general truths or the operation of general laws Branch of study that is concerned with observation and classification of facts concerned with the physical world and its phenomena

In order to do science we have to make the following assumptions: There is order to the universe (even if it is chaotic order) The human mind is capable of comprehending this order If conditions are the same, the results of any study will be the same

‘God does not play dice with the universe.’

Or does She?

Science can only state what is, not what should be. Albert Einstein

Which of the following statements can be tested scientifically? Most of the energy coming from the sun is in the form of visible light. Unicorns exist. Shelley wrote beautiful poetry. The Earth was created over four billion years ago. Diamond is harder than steel. Diamonds are more beautiful than rubies.

The claim is sometimes made that the scientific method produces closer and closer approximations to "reality." Is this a scientific statement? Why or why not?

The Scientific Method

Scientists develop their knowledge by observation and experimentation Observation is used in two ways: 1. Inductive reasoning - discovering general principles by the careful examination of specific cases. Here the scientist organizes data (facts) into categories and asks what they have in common 2. Deductive reasoning starts with general cases and proceeds to specific cases - it makes relationships clearer and allows predictions to be made

Scientific knowledge advances by a method known as "strong inference" Strong inference works as follows: 1. Make an observation or measurement 2. State an hypothesis 3. Test the hypothesis 4. Publish the results 5. Restate the hypothesis, test again

Observation Semmelweis (1856), observed in hospitals in Vienna, that 5X the number of women died during childbirth if they were attended by a physician as compared to being attended by a nurse (deaths mostly due to “childbed fever”). One of his colleagues died of childbed fever after cutting his hand with a scalpel during an autopsy. Doctors are often doing autopsies before attending to childbirths.

Observation Hypothesis (inductive reasoning) Hypothesis Semmelweis hypothesized that “cadaveric matter” was transmitted from the autopsy room to the delivery room.

Observation Hypothesis Prediction Washing hands would eliminate the (inductive reasoning) Hypothesis (Deductive Reasoning) Prediction Washing hands would eliminate the cadaveric matter and reduce childbed fever. null hypothesis vs. alternative hypothesis

Observation Hypothesis Prediction Experiment Observation (inductive reasoning) Hypothesis (Deductive Reasoning) Experimental design •controls •dependent variable (what’s affected) •independent variable (what’s the “cause”) •predicted data (must be able to differentiate between null and alternative hypotheses) Prediction Experiment Observation correlation ≠ causation

correlation ≠ causation

(Observation = Prediction?) (inductive reasoning) Hypothesis (Deductive Reasoning) Prediction [Experiment] Experiment Observation Childbed fever deaths absent when physicians washed their hands Analysis (Observation = Prediction?)

Childbed fever deaths absent when physicians washed their hands

Semmelweis

(Observation = Prediction?) (inductive reasoning) Hypothesis (Deductive Reasoning) Prediction [Experiment] Experiment Observation Analysis (Observation = Prediction?) Transmission of cadaveric matter causes childbed fever Conclusion

(Observation = Prediction?) (inductive reasoning) Hypothesis (Deductive Reasoning) Prediction What other hypotheses could be made from the conclusion? [Experiment] Experiment Observation Analysis (Observation = Prediction?) Conclusion

(Observation = Prediction?) (inductive reasoning) Hypothesis (Deductive Reasoning) Prediction What would you predict from your hypothesis? [Experiment] Experiment Observation How would you test it experimentally? Analysis (Observation = Prediction?) Conclusion

Observation Hypothesis Prediction Theory Law Fact [Experiment] (inductive reasoning) Hypothesis (Deductive Reasoning) Prediction Theory Law Fact [Experiment] Experiment Observation Analysis (Observation = Prediction?) Generalization (Deductive Reasoning) Conclusion

Final Hypothesis Supported Scientific method is a repetitive process that leads to the building of theories Initial Observation reasoning? New Hypothesis Hypothesis New Experiment Experiment New Observation Observation/ Data Analysis Hypothesis not Supported Interpretation Final Hypothesis Supported Theory

Preconceptions can influence scientific method Identifying Patterns Observations Experimentation Data Preconceptions Hypothesis Prediction For childbed fever: “vapors”, spontaneous generation, women as “weak”

Theories in science build from the accumulation of multiple investigative efforts accumulated scientific data formulation of hypothesis observation and experimentation new data conclusions 1 2 3 etc theory communicable disease

Summary The scientific method is in essence a process of observing natural phenomena which leads to the asking of questions about those phenomena which leads to the offering of explanations that can subsequently be tested

Mystery Box Hand out mystery boxes Do hypothesis testing exercise