Past exam of the philosophy of science supplementary subject of the University of Oxford / 2018 / 1 / b / Solution

A scientist should take a sceptical scenario seriously when it exposes a credible way in which the evidence could be misleading and there is a useful way to investigate that possibility. A shared instrument offset, a software error copied across analyses, or an unrecognized background signal can survive the appearance of repeated agreement. Such possibilities motivate independent calibration, changes of apparatus and analysis, and deliberately varied experiments. Mere repetition using the same error-prone chain is weaker than agreement among genuinely independent tests.

Consider two detectors that report the same departure from a predicted signal. Their agreement supports a new effect less strongly if both use the same calibration source and processing program. A proposed common failure is not defeated merely by observing that both detectors agree. An independently constructed detector, measurements at several settings, or analysis of deliberately hidden test signals can make the failure scenario and the target hypothesis predict different outcomes. Here scientific doubt generates a better test rather than an unlimited demand for reassurance.

A radically global sceptical scenario is different. If it is stipulated to reproduce every possible observation and experiment, it supplies no empirical contrast to investigate. That does not make it logically contradictory or prove it false. It limits its role in choosing among scientific models. A researcher cannot improve a detector by an experiment whose outcome is stipulated to be identical whether all experience is globally deceptive or not.

The line is not simply between imaginable and unimaginable errors. Limited time and resources require attention to plausibility, consequences and discriminating power. A low-probability fault may deserve a check when it could invalidate an entire result and is inexpensive to test. Conversely, inventing an unconstrained auxiliary hypothesis after every contrary result can insulate a favoured theory from criticism. The Duhem problem explains why a failed prediction does not isolate the guilty assumption; it does not make every rescue equally well evidenced.

A scientist can therefore combine fallibilism with justified confidence. Results can be warranted by calibration, independent methods and successful interventions without excluding every logically possible deception. Productive scientific scepticism identifies concrete vulnerabilities and seeks evidence against them. It neither assumes that every appearance is reliable nor treats the absence of Cartesian certainty as the absence of scientific knowledge.