 Biographical material about Leśniewski is fairly sparse, and it is even harder to gain a clear idea of what he was like as a person. Jadacki (2016) contains much new information about Leśniewski, his family, and his relationships with colleagues and contemporaries, but even here the man behind the words and (invariably unsmiling) photographs is not easily discernible. A photograph of him in Twardowski’s seminar in 1913 shows a short, dapper man with a goatee and a flamboyant neckscarf, as described by Łukasiewicz. In later photographs from the same period he lacks the goatee but retains a moustache. Two well-known later photos show a stiffly-posed, stocky, clean-shaven man in a business suit with the slicked-back hair of the period, looking more like a bank manager than a professor of logic, except for an intense stare. Leśniewski was known to be a fierce critic of what he considered unclear, which was pretty well everything. His stock complaint was that he could not understand what speakers were saying, or writers were writing. In the light of his pathological inability to see beyond the literal meaning on the page to any intended but inaccurately expressed meaning this is unsurprising, but also unendearing. In the early 1920s Marjan Borowski, the editor of Przegląd Filozoficzny, complained to Twardowski that people were afraid to submit papers or give talks in Warsaw because they were fearful of being criticised by Leśniewski, though he added with some glee that the scourge of God had risen up against him in the shape of one Tajtelbaum – the young Tarski. Even the phlegmatic Twardowski found his former student irritating: in a diary entry for 12 August 1930 he complains, “In general those who behave according to Lesniewski’s model ask very arbitrarily for analysis where it is convenient to them—if, however, one of them asks for analysis where it is not convenient to him, they turn to intuition. And if the opposer in the discussion sometimes tries to turn to intuition, they reply ‘We don’t understand what you consider to be intuitively given’.” Twardowski’s 1921 paper ‘Symbolomania and Pragmatophobia’ is a plea for philosophers not to put symbols above things, and while its ostensible target is the French physicist Henri Bouasse, it is clearly implicitly directed against Łukasiewicz and Leśniewski and their students.