On the impossibility of natural laws in Kant's empirical psychology. A critique of Michael B. McNulty's interpretation

MARTIN ARIAS ALBISU

Lisboa

Congreso; IX Kant Multilateral Colloquium: Justice, Peace, and Cosmopolitan Values; 2021

Universidad de Lisboa

In “Kant on Empirical Psychology and Experimentation”, Michael B. McNulty holds that, for Kant, empirical psychology does not have natural laws. As candidate natural laws of empirical psychology cannot be tested by experimentation (MAN, AA 04: 471), they cannot be more than mere empirical regularities that, in contrast to empirical natural laws of chemistry, do admit exceptions. McNulty illustrates this interpretation by comparing, mainly, chemistry as an experimental science with psychology as a non-experimental science.The aim of this paper is to show that McNulty’s interpretation is incorrect. My critique contains two main theses. In the first place, McNulty’s claim according to which chemistry, in virtue of the use of hypotheses controlled by experimentation, can achieve natural laws with true or strict universality, i.e., that does not admit exceptions (McNulty, 2018, p. 2710), does not find support in Kant’s texts. Being based on experimentation, the laws in question can only become more probable thanks to the successful realization of experiments designed to test them. McNulty does not offer a valid argument to justify the leap from the high probability of an empirical law to its strict universality (on the probability of empirical laws, considered as hypotheses, see Log, AA 09: 84-86). In the second place, the absence of experimentation in empirical psychology does not imply that in this discipline empirical natural laws with strict universality are not possible (McNulty, 2018, p. 2713), but that even probable empirical natural laws are not possible, since only through experimentation can empirical natural laws acquire probability, as it happens in the case of chemistry. It is this impossibility of acquiring probability through experimentation that affects candidate natural laws of empirical psychology, and not, as McNulty holds, the absence of strict universality. Since these candidate laws cannot obtain probability, they must not be considered as natural laws in strict sense, because the lack verifiable explanatory potential.