Basic Assumptions and Limitations of Science
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If you feel that your students are sufficiently ready (probably 10th-12th grade), you may want to share the following Basic Assumptions of Science (and possibly the Basic Limitations of Scientific Knowledge, as well). These assumptions and limitations form the basis for the several Key Concepts of Science and the handy “Rules of Science” mentioned elsewhere on the ENSI site.


  • 1. The world is real. The physical universe exists apart from our sensory experiences.
  • 2. Humans can accurately perceive and understand the physical universe.
  • 3. Natural processes are sufficient for understanding the natural world.
  • 4. Nature operates uniformly throughout the universe in space and time.



  • A. Our senses have their own biological limitations. Even technological devices for extending those limitations have their own limits of accuracy and range.


  • B. Our mental processing of sensory data is not always reliable. We are influenced by previous experiences, biases, and degrees of attention, all contingent* on circumstances.
  • C. It’s impossible to know if we have considered all possible alternative explanations.


  • D. Scientific knowledge is necessarily contingent knowledge (and therefore uncertain). It is not absolute knowledge (certain and eternally true). It is dependent on available evidence, circumstances, tools and our analysis.

NEVERTHELESS, scientific knowledge is the most reliable knowledge we can have about the natural world and how it works. This is because scientists have developed a methodology for learning based on principles of critical thinking and reducing bias.


*Contingent = depending on existing technology and current ways of thinking.

Adapted from “Nature of Modern Science and Scientific Knowledge” by Martin Nickels, Professor of Anthropology.