IB Philosophy 6.1.2 Demarcation Notes

The Problem of Demarcation

1. As discussed in 6.1.1, the nature of science raises fundamental questions about what makes scientific inquiry distinctive. The demarcation problem takes this further by asking precisely where the boundary lies between science and everything that falls outside it, from pseudo-science to non-scientific belief systems.
2. The demarcation problem is not merely an abstract philosophical puzzle but has significant practical consequences. Decisions about what counts as science affect government funding, educational curricula, legal proceedings, and public policy, making the question of scientific legitimacy both philosophically and socially urgent.
3. Throughout history, various activities have claimed the status of science without meeting widely accepted standards. Astrology, phrenology, and alchemy are classic examples of practices that once enjoyed considerable intellectual respectability but are now generally classified as pseudo-science.
4. The logical positivists were a group of early twentieth-century philosophers (based mainly in Vienna) who proposed that a statement only has genuine meaning if it can be tested by observation. Their demarcation criterion follows directly: a statement is scientific only if it can be verified through direct observation or logical reasoning from observable facts.
5. A.J. Ayer, one of the most prominent English-language logical positivists, put this bluntly in Language, Truth and Logic (1936): a statement only qualifies as meaningful, and therefore potentially scientific, if there is some way, at least in principle, to check it against sensory experience or work it out through logic.
6. However, the verification principle faced serious difficulties. Many statements that scientists regard as genuinely scientific (such as universal laws like all metals expand when heated) cannot be conclusively verified because they make claims about an infinite number of cases, most of which have not been observed.
7. Karl Popper recognized these limitations and proposed an alternative criterion that would become one of the most influential contributions to twentieth-century philosophy of science. Rather than asking whether a theory can be verified, Popper asked whether it can be falsified.
8. Thomas Kuhn offered a fundamentally different approach to the demarcation problem. Rather than seeking a single logical criterion, Kuhn argued that the distinction between science and non-science depends on the social and institutional practices of scientific communities.

Popper's Falsificationism

1. Karl Popper developed falsificationism as his answer to the demarcation problem, first presented in The Logic of Scientific Discovery (1934). Popper argued that the capacity to be proven wrong, not the capacity to be proven right, is what makes a theory genuinely scientific.
   1. For Popper, a scientific theory must make bold predictions that could potentially conflict with observed evidence.
   2. A theory that is compatible with every possible observation, one that cannot be refuted no matter what happens, is not scientific but rather unfalsifiable and therefore pseudo-scientific.
2. Popper used Marxism and Freudian psychoanalysis as his primary examples of pseudo-science. He observed that followers of these theories could always reinterpret any apparent counterevidence to fit their framework, rendering the theories immune to refutation and therefore unscientific by his criterion.
3. By contrast, Popper regarded Einstein's general theory of relativity as a paradigm of genuine science. Einstein's theory made specific, testable predictions (such as the bending of light by gravity) that could have been shown to be false by observation, giving the theory strong empirical support when confirmed.
4. Popper's criterion has significant strengths, providing a clear logical standard for distinguishing science from non-science. It also explains why science progresses: scientists actively seek to test and overthrow existing theories, driving the field forward through critical scrutiny rather than mere confirmation.
5. However, falsificationism faces an important objection from the Duhem-Quine thesis: scientific hypotheses are never tested on their own but always alongside a whole package of supporting assumptions, such as beliefs about how instruments work and what background conditions hold. Philosophers call these auxiliary assumptions.
6. When a prediction fails, scientists can always modify an auxiliary assumption rather than abandoning the core theory, making it difficult to establish a decisive falsification in practice.

Objections and the Concept of Corroboration

1. Another difficulty is that important theories have sometimes been retained despite initial inconsistency with evidence.
2. Newton's theory of gravity could not initially account for the observed orbit of Uranus, yet scientists postulated the existence of Neptune rather than rejecting the core theory, and Neptune was subsequently discovered.
3. Retaining the theory in the face of apparent falsification proved scientifically productive, demonstrating that Popper's simple falsification rule cannot capture the full complexity of scientific practice.
4. The asymmetry between verification and falsification is central to Popper's position.