Philosophy of science studies how scientific knowledge is built, tested, explained, and revised. This cheat sheet helps students compare major views about evidence, theories, and scientific method. It is useful for evaluating claims about what makes science reliable and how it differs from pseudoscience.
Students need these tools to write clearer arguments about experiments, models, and scientific progress.
Core ideas include falsifiability, induction, underdetermination, paradigms, and the difference between explanation and prediction. Scientific claims are judged by evidence, logical consistency, testability, scope, simplicity, and ability to survive criticism. Philosophers disagree about whether science discovers truth directly or mainly creates useful models.
A strong philosophy of science answer connects a position to examples, objections, and standards of evidence.
Key Facts
- Falsifiability means a scientific claim must risk being shown false by possible observations, such as 'all metals expand when heated' being tested by heating metals.
- Induction moves from observed cases to a general rule, so observing 100 white swans supports but does not prove the claim 'all swans are white.'
- Deduction moves from general premises to a necessary conclusion, such as 'all mammals are warm-blooded' and 'whales are mammals' imply 'whales are warm-blooded.'
- A hypothesis is stronger when it makes precise, risky predictions that could fail, rather than vague claims that fit any possible result.
- Underdetermination means the same evidence can sometimes support more than one theory, so scientists also use simplicity, coherence, and explanatory power.
- Kuhn's paradigm theory says normal science works within an accepted framework until anomalies accumulate and may lead to a scientific revolution.
- Scientific realism claims successful scientific theories are at least approximately true about unobservable things, while instrumentalism says theories are tools for prediction.
- Correlation alone does not prove causation because two variables may be linked by coincidence, a hidden common cause, or a reversed cause-effect relationship.
Vocabulary
- Falsifiability
- Falsifiability is the feature of a claim that allows possible evidence to show it is false.
- Induction
- Induction is reasoning from particular observations to a broader generalization or pattern.
- Paradigm
- A paradigm is a shared scientific framework that includes theories, methods, standards, and example problems.
- Anomaly
- An anomaly is an observation or result that does not fit what a current theory or paradigm predicts.
- Underdetermination
- Underdetermination is the problem that available evidence may not uniquely determine which theory is correct.
- Scientific Realism
- Scientific realism is the view that successful scientific theories describe a mind-independent world, including unobservable entities.
Common Mistakes to Avoid
- Treating one confirming example as proof is wrong because inductive evidence can support a theory without making it certain.
- Calling a claim scientific just because it sounds technical is wrong because scientific claims must be testable, evidence-based, and open to revision.
- Confusing falsifiable with false is wrong because a falsifiable claim may be true, but it must be possible in principle to test it against evidence.
- Ignoring background assumptions is wrong because tests often depend on instruments, measurement methods, and auxiliary hypotheses.
- Assuming science changes only by adding facts is wrong because theory change can also involve new concepts, standards, and interpretations of evidence.
Practice Questions
- 1 A student observes 12 plants growing faster with fertilizer and concludes that all plants grow faster with fertilizer. Identify the type of reasoning and explain one limitation.
- 2 A theory predicts that 8 out of 10 samples will react with a chemical, but only 3 out of 10 react. Explain how this result could count as an anomaly.
- 3 Two theories both explain 5 known observations, but Theory A makes 2 new precise predictions while Theory B makes none. Which theory is stronger by Popper's standard and why?
- 4 Explain whether the claim 'invisible forces always make events happen exactly as they do' is scientific, using falsifiability and testability in your answer.