Marginal comments on the thought of Hume, Popper and Kuhn

Abstract

When Popper states that a scientific theory may only be falsified, never verified, he appears to come in support of the Hume opinion on the impossibility of generalizing single observations, thus negating the possibility of predictions. However, the ideas of the two philosophers are very different and need to be accurately interpreted. Hume, using the example of the white and black swam, exaggerates in minimizing the validity of observations. In his example, he uses a nonlinear system where variations both of the initial and contour conditions can occur (in fact, living systems are subject to mutations), and therefore does not allow for predictions. On the contrary, physical and chemical systems work by fixed laws (variations of initial and contour conditions do not occur). For these systems, a series of observations allows to make generalizations and legitimate predictions. Furthermore, Hume argument (nature uniformity cannot be guaranteed in a future time), stating that Universe fixed laws may be subject to unpredictable change, appears weak. In that case our Universe would cease existing, whereas science is concerned only with events occurring within the laws that govern the Universe till now, and they are not subject to change. Coming to Popper, his falsification does not pertain observations and their power to describe the reality. On the contrary, it refers to the theoretical model imagined to explain the observed phenomena and to make predictions on future events. In fact, every scientific theory encompasses two distinct parts. The description of the real world is necessarily empirical, based on observed events, whereas the theoretical model is a purely mental product, imagined to explain the observed events. It is just the theoretical model that can never be considered definitive and needs to be changed every time that falls in defect with respect to new evidence. Popper views observation as an essential instrument to reach a realistic description of the world. Kuhn relativism about science appears debatable. Being a historian, he is interested to the peculiar ways of thinking of men in different times, and he puts these theories on the same intellectual level. Correspondence to reality is not discriminating, in Kuhn view, since it is seen within the peculiar vision of the world envisaged by each theory. Kuhn relativism encounters also the difficulty of justifying the accumulation of scientific knowledge.