PSYCHOLOGICZNE ZASADY ROZUMOWANIA DEDUKCYJNEGO

• Published in: Roczniki filozoficzne 1987-01, Vol.35/36 (4), p.5-26
• Main Author: KROPLEWSKI, ZDZISŁAW
• Format: Article
• Language: Polish
• ISSN: 0035-7685; 2450-002X

The present paper deals with the psychological principles which govern the process of deductive reasoning. It is a critical review of hitherto psychological research in this matter, which research gives grounds for empirical research. The author concentrates on the process of reasoning which reasoning deals with the categorical syllogism and the prepositional calculus (especially modus ponens and modus tollens). The problem of "logicality" of the process of reasoning has been raised here. The author presents various approaches to the question of the logicality of the process of reasoning, i. e.: — operational (here we refer to the correctness of the results of the reasoning process), — structural (it is emphasized here that mental operations are performed by people), — formal (man has formal abilities to reason). Then the author discusses the logical principles of the reasoning process in order to compare them with those in fact used by people. Among the principles which govern the reasoning process based on the categorical syllogism and those discovered by psychologists are the following: — effect of the atmosphere of premisses, — effect of the syllogistic figure, — effect of conversion. On the basis of those discovered principles, there were some attempts to create models explaining the reasoning process, and especially the fact that people make errors when they reason. However, none of those theories explain the reasoning process completely, and even in relation to the categorical syllogism there were only partial explanations. There is, then, a need for new research in this respect, and one must create such a model that would take into account the effects that have been hitherto discovered. In relation to the reasoning process based on the prepositional calculus, though, there have not been found any explicit principles accountable for the errors made by people. Psychologists draw our attention to the fact that people understand causality and negation in a different way than it exists in formal logic. Consequently, the author arrives at a conclusion that on the grounds of hitherto research one cannot say what precisely the psychological process of reasoning consists in. It is certain that it does not fall under the principles of formal logic. The regularities that have been found up to now, however, provide us with only a partial explanation of what the actual process of reasoning consists in.