Search for: [Subject and Keywords = natural sciences and philosophy] OR [Subject and Keywords = philosophy \(19 c.\)] OR [Subject and Keywords = Filozofia \-\- 19 w. \[JHPBN\]] OR [Subject and Keywords = Nauki przyrodnicze a filozofia \-\- artykuł \[JHPBN\]] OR [Title = W sprawie filozofji naukowej] OR [Title = W sprawie filozofji naukowej] OR [Creator = Avenarius, Richard \(1843–1896\)] OR [Creator = Avenarius, Richard \(1843–1896\)]