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Why can a scientific law be modified after new experimental evidence?
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principles of physical science
Figure 1: Data in the table of the Galileo experiment. The tangent to the curve is drawn at t = 0.6.
Scientific laws are modified or rejected when new experimental evidence contradicts their predictions because they are not logically necessary truths; rather, they rest upon the evidence of experience. In the philosophy of science, scientific knowledge is inherently tentative and provisional.12
The process of modification is driven by several key principles:
- Falsifiability: According to the criterion of falsifiability, a theory is scientific only if it is possible to establish that it is false. Because disconfirming observations are always possible, theories are never finally confirmed; they are only incrementally corroborated until evidence suggests otherwise.3
- Eliminative Testing: Scientists often test hypotheses by attempting to eliminate those that fail to match experimental results. When evidence conflicts with a theory, scientists may re-evaluate the hypothesis or the auxiliary assumptions used in the experiment.2
- Probabilistic Updating: Approaches like Bayesianism suggest that scientists rationally modify the probability assigned to a hypothesis as new evidence is acquired, allowing for the refinement or abandonment of ideas as data accumulates.4
Ultimately, science relies on the integrity of responding to evidence, ensuring that our understanding of the natural world remains grounded in observable reality rather than dogma.12