Natural Sciences & Knowledge (DP IB Theory of Knowledge): Revision Note

Natural sciences & knowledge

• The natural sciences study the natural world, aiming to produce justified explanations and predictions based on observation and testing

• Natural science subjects include:

  • biology

  • chemistry

  • physics

  • geology

  • astronomy

• Scientific claims focus on patterns and relationships that can be investigated using evidence from the physical world

• The culture of scientism (highkly valuinga nd trusting scientific knowledge) someties equates knowledge in the Natural Sciences with certainty

• Scientific conclusions can change when new evidence is found or alternative methods are used

  • Scientific claims are always judged by how well they fit evidence and survive testing

Scientific questions vs non-scientific questions

• A scientific question is one that can be investigated using observation or measurements, while non-scientific questions are not testable, e.g. because they are concerned with values, meaning or purpose

  • The scientific question “Which treatment reduces blood pressure more?” is testable with data

  • The non-scientific question “Is it morally acceptable to use animals in testing?” requires ethical reasoning

Laws, theories and models

• Evaluating scientific knowledge involves judging how well laws, theories, and models fit the evidence and how effectively they predict new observations

  • Scientific law: description of a consistent pattern or relationship in nature, often summarised in a general statement or equation

  • Scientific theory: a well-supported explanation of why a pattern happens; a theory should be built from multiple lines of evidence and be able to generate predictions

  • Scientific model: a simplified representation used to explain, predict or test ideas when the real system is too complex to work with directly

Limits of scientific inquiry

• The natural sciences are limited in their scope, e.g.:

  • scientific inquiry is limited to questions that can be investigated with evidence from the natural world

  • practical constraints, such as measurement limits, technology, cost and ethical restrictions, may limit which experiments are possible

  • scientific conclusions are limited by assumptions in methods and models, so results may not transfer to different conditions

• Recognising limits supports better justification because it prevents overstating what the evidence shows