ABSTRACT
According to Popper, truth is the aim of science. But the scientific condition is one of ignorance. For, as we shall see in the next section of this chapter, we are never entitled to claim to know the truth of a scientific theory or hypothesis. In view of the pessimistic induction this might not seem a rash position. Popper goes further and denies that we can ever know the truth of even the most low-level observation report. Naively one might think that one could at least have good reasons on occasion for thinking that one hypothesis or observation report is more likely to be true than false. Not so, says Popper. In Section 3 I outline his reasons for this very strong claim, which amounts to the rejection of all inductive argumentation. That is, Popper denies the legitimacy of any argument in which the premises purport to support the conclusion without entailing it. A scientist who has shown that when 1000 randomly selected samples of sodium were placed in a flame it turned yellow has, according to Popper, no reason to say that the hypothesis that sodium turns a flame yellow is probably true. However, if one piece of sodium were to fail to turn a flame yellow we should be entitled to reject the hypothesis. For the premise ‘This piece of sodium did not turn the flame yellow’ entails the conclusion ‘Not all pieces of sodium turn yellow when placed in a flame’. Since only deductive arguments are legitimate, the method of science is not evidence gathering but conjecture and refutation. The best we can hope for is the refutation of hypotheses.
