Questions: Theoretical Virtues in Theory Choice

Question 1

In 16th-century astronomy, what role did simplicity play in the initial case for the Copernican model over the Ptolemaic one?

• A. It was irrelevant — astronomers only considered predictive accuracy, and Copernicus was clearly more accurate
• B. It served as a tie-breaking non-empirical criterion, since both models fit the available data comparably but heliocentrism explained retrograde motion without ad hoc epicycles
• C. It was used to prove mathematically that epicycles are physically impossible
• D. It convinced the Church to endorse Copernicus because simpler theories are easier to teach

Answer: (B)

At the time of Copernicus, the Ptolemaic model's predictive accuracy was comparable to the early Copernican model — empirical data did not clearly favor either. The heliocentric model's advantage was theoretical: it explained retrograde planetary motion as a natural geometric consequence of Earth and other planets orbiting the Sun, while the Ptolemaic model required a separate epicycle for each planet's retrograde behavior. Simplicity and explanatory scope were the deciding virtues, not empirical accuracy. This is a paradigm case of theory choice under underdetermination.

Question 2

A scientific realist and an anti-realist both agree that scientists prefer simpler, more coherent theories. Where do they disagree?

• A. The anti-realist thinks simplicity is a truth-tracking virtue; the realist thinks it is merely pragmatic
• B. The scientific realist thinks simplicity tracks truth because the world is structured; the anti-realist thinks it is a useful cognitive preference that says nothing about unobservable reality
• C. The realist denies that simplicity plays any role in science; only empirical fit matters
• D. Both think simplicity is truth-tracking; they only disagree about which theories are actually simpler

Answer: (B)

The core debate is whether theoretical virtues are epistemic (truth-conducive) or pragmatic (useful but not truth-indicating). Scientific realists argue the world's deep structure favors simpler theories, so preferring simplicity is a reliable guide to truth. Anti-realists and instrumentalists counter that simplicity is a feature of how human minds organize information — it aids prediction and research without warranting claims about unobservable structure. This disagreement directly bears on the argument from success: if virtues track truth, science's success confirms realism; if not, success is compatible with anti-realism.

Question 3

Theoretical virtues like simplicity and coherence are mainly relevant when two theories make literally identical empirical predictions in most possible experiments.

• T. True
• F. False

Answer: False

Theoretical virtues operate whenever evidence underdetermines theory choice — which, as the underdetermination thesis shows, is essentially always. Even when two theories make slightly different predictions, current data may not yet discriminate between them, and virtues guide the choice of which to pursue. Moreover, theories are often chosen to guide future research before all predictions are even known. Virtues don't wait for empirical equivalence; they function as guides whenever the evidence doesn't uniquely determine the best theory.

Question 4

A scientific realist would take a theory's greater simplicity and coherence with existing science as some evidence that the theory is more likely to be approximately true.

• T. True
• F. False

Answer: True

Scientific realists hold that theoretical virtues are truth-tracking: a simpler theory is more likely to have identified real underlying structure because the world is genuinely structured rather than chaotic. Coherence with existing science similarly suggests that the theory is latching onto real regularities that other successful theories also capture. This is the realist's grounds for taking virtues epistemically seriously — they are indicators of truth, not just aesthetic preferences.

Question 5

What is the central philosophical question about theoretical virtues, and why does the answer matter for scientific realism?

Model answer: The central question is whether theoretical virtues (simplicity, coherence, fruitfulness, scope) are epistemic — reliably indicating which theories are true — or merely pragmatic — useful for prediction and problem-solving without bearing on truth. If they are epistemic, then scientists' preference for simpler, more coherent theories is a form of evidence for those theories' approximate truth, supporting scientific realism. If they are merely pragmatic, theory choice based on virtues says nothing about which theory actually tracks reality, and the striking success of mature science could be a coincidence — undercutting the standard realist argument from the success of science.

This debate is not merely academic. It determines whether 'best explanation' reasoning in science is epistemically legitimate or just heuristically useful. Anti-realists like van Fraassen argue virtues select empirically adequate theories, not true ones. Realists like Lipton argue that virtues reliably guide us toward the truth because they track features of a unified, structured world.