The Nature of Science Truth Proof Belief Evidence Debate Consensus

Science is about probabilities, not certainties

• The hypothesis: Smoking causes lung cancer
• Reality: Smoking dramatically increases one’s chances of developing lung cancer

Anecdotes vs. Studies

• Anecdotal evidence: “My grandmother smoked a pack a day for 60 years, she lived to be 75.”
• Scientific study: Monitor the health of 1000 smokers and non-smokers for 20 years. Compare rates of lung cancer, longevity, etc.

Power of suggestion

Have you heard claims that vaccines can sometimes cause autism in children? Which of the following is true:

• Studies show that there is a slight risk of developing autism due to vaccines but the benefit outweighs the risk
• Studies have shown that there is no cause-and-effect relationship between vaccines and autism
• Studies into the proposed links between autism and vaccines have not yet been conducted

Conclusion

• Science vs. non-science
• Science seeks explanations that rely solely on natural causes
• progresses through development and testing of models of nature
• models must make testable predictions
• A scientific theory
• A model that explains a wide variety of observations in terms of a few general principles
• Has survived repeated and varied testing
• Subject to modification as new data and observations are acquired