Questions: Incommensurability of Paradigms

Question 1

The concept of 'mass' across Newtonian mechanics and special relativity illustrates which aspect of incommensurability?

• A. Methodological incommensurability — the two paradigms use different experimental procedures to measure mass
• B. Semantic incommensurability — 'mass' participates in different conceptual networks in each theory, making direct translation impossible
• C. Empirical incommensurability — the two theories make contradictory numerical predictions about mass measurements
• D. There is no incommensurability here — mass is a physical quantity both theories measure identically

Answer: (B)

The mass example illustrates semantic incommensurability: the term 'mass' has different theoretical roles in the two frameworks. Newtonian mass is absolute and observer-independent; relativistic invariant mass participates in energy-mass equivalence and Lorentz-covariant structure. You cannot simply substitute one for the other — the conceptual networks have different shapes. Option D is exactly the assumption incommensurability denies; option A (methodological incommensurability) is a real but distinct phenomenon.

Question 2

Early Copernican astronomy did not predict planetary positions significantly better than the Ptolemaic system it was replacing. What does Kuhn's analysis of this case show about scientific paradigm change?

• A. The Copernican revolution was irrational — scientific revolutions require clear empirical superiority to be justified
• B. Empirical accuracy is always the decisive factor; other values like simplicity merely rationalize the chosen outcome
• C. Paradigm choice can be guided by non-empirical values like simplicity and explanatory coherence without this being irrational
• D. Incommensurability means paradigm shifts are purely sociological events with no rational justification

Answer: (C)

Kuhn argues that paradigm choice can be partly driven by non-empirical scientific values — simplicity, coherence, fruitfulness — when predictive accuracy is similar or even initially worse. This is not irrational; it is rational judgment that cannot be reduced to an algorithm. Option D misrepresents Kuhn — he explicitly rejected the relativist conclusion. The historical case shows that 'most empirically accurate' is not the only or always the decisive criterion for paradigm choice.

Question 3

Incommensurability means that successive paradigms share no values and cannot be compared in any meaningful way.

• T. True
• F. False

Answer: False

This is an overstatement that Kuhn explicitly resisted. Incommensurability means paradigms cannot be evaluated by a single neutral algorithm — not that they cannot be compared at all. Kuhn affirmed that scientists across paradigm shifts share certain values: accuracy, consistency, scope, simplicity, fruitfulness. What differs is how these values are weighted and what counts as satisfying them. 'No common measure' is not the same as 'no comparison possible.'

Question 4

Paradigm shifts can be rational even without paradigm-neutral criteria, because scientists share values like simplicity and fruitfulness that guide choice even when weighted differently across paradigms.

• T. True
• F. False

Answer: True

This is Kuhn's own resolution of the rationality problem. Incommensurability prevents algorithmic decision procedures but not rational deliberation. Scientists arguing for or against a new paradigm appeal to shared values; they just cannot derive a uniquely correct verdict by calculation. The outcome requires judgment, which is a form of rationality even when it does not yield unanimity. Kuhn compared paradigm change to a gestalt switch: rational, but not deductive.

Question 5

Explain the rationality problem that Kuhn's incommensurability thesis creates, and outline how Kuhn proposed to preserve rational scientific progress despite it.

Model answer: The problem: if paradigms supply their own standards of evaluation, and those standards change across paradigm shifts, there is no neutral standpoint from which to rationally choose between competing paradigms. Each paradigm judges itself by its own criteria; paradigm change looks like conversion rather than argument. Kuhn's resolution: scientists do share certain epistemic values across paradigms — accuracy, consistency, scope, simplicity, fruitfulness — even when they weight them differently. Paradigm choice is guided by these shared values through expert judgment rather than algorithmic application. The key distinction: incommensurability means the choice cannot be fully determined by shared standards, not that there are no shared standards at all. Rational deliberation remains possible; certainty of outcome does not.

Critics on both sides found this unsatisfying: Feyerabend thought Kuhn conceded too little to relativism and pushed toward full 'anything goes' methodology; scientific realists argued Kuhn conceded too much, threatening cumulative scientific progress. Kuhn's middle position — rationality without algorithms — remains the most influential response to the problem.