As it is broadly accepted, typical uses of demonstratives are accompanied by demonstrations. The concept of demonstration, however, manifests the action–product ambiguity analogous to that visible in the opposition between jumping and the resulting jump, talking and the resulting talk or crying and the resulting cry. It is also a heterogeneous concept that enables demonstrations to vary significantly. The present paper discusses action–product ambiguity as applied to demonstrations as well as the heterogeneity of the latter. An account that acknowledges ambiguity (...) and heterogeneity of demonstrations is sketched in the paper. It is argued that it has a rich explanatory and descriptive potential. (shrink)

In this paper, I analyze the shift in Twardowski’s views between his early psychologistic theory of logic and his later anti-psychologistic theory. In particular, I point out that the interpretation suggesting that this change merely involves Twardowski enriching his ontology with products encounters a certain problem in light of his earlier views. To present this problem more precisely, I discuss the foundations of Twardowski’s theory of products, focusing on aspects relevant to the issue of psychologism. Based on this, I reconstruct (...) Twardowski’s theory of logic and highlight where he identified the fallacy of psychologism. I contrast this reconstructed theory with Twardowski’s earlier views at key points and demonstrate that the difference between his early psychologistic theory and his later anti-psychologistic theory is a matter of a shift in emphasis rather than a significant change in the theoretical system itself, and that Twardowski himself understood it as such. (shrink)