The demarcation problem asks how to tell science from non-science, including pseudoscience, and why that boundary matters.
Early thinkers like Aristotle tied “scientific” knowledge to causes, logical demonstration, universals, and apodictic certainty, though some ancient “natural” explanations leaned little on observation.
Later, logical positivism proposed verificationism: a claim is meaningful and “scientific” if it is verifiable in the observable world or from derived experience; claims beyond that were classed as metaphysics.
Karl Popper rejected verifiability and offered falsifiability instead: a claim counts as scientific if it could in principle clash with possible observations; he treated this as necessary and sufficient, though critics noted it can exclude some real science and admit some pseudosciences.
Thomas Kuhn shifted focus to normal science as puzzle-solving within a paradigm (a shared problem-solving framework) and contrasted it with fields like astrology that, he argued, generate no research puzzles; Popper objected that this makes demarcation sociological.
Paul Feyerabend and Imre Lakatos questioned whether science has any special method at all.
Paul Thagard called a theory unscientific when it lags behind alternatives, has many unsolved problems, and its community avoids fair tests and selectively handles evidence; by this view, pseudoscience is stagnation without active investigation.
Larry Laudan concluded no single demarcation rule works and urged asking instead which beliefs are reliable or unreliable. Afterward, some suggested multiple criteria or “family resemblances.”
The stakes include education, public policy, critical thinking in democracy, high-profile disputes such as climate-change denial, resisting political or religious authority over factual truth, and even comparisons to spotting fake news.
Online Resources
- Demarcation problem / Wikipedia
- Science and Pseudo-Science / SEP
- Pseudoscience and the Demarcation Problem / IEP
Please Note: This is my personal summary of the topic, shared both for my own records and in the hope it may be helpful to you. AI was used in parts to assist with the process.