  Leśniewski was however not lacking in a certain heavy humor. Lejewski reported that he once mocked a Warsaw Professor of Classics for wearing sunglasses (then rather rare): “Is the world too dazzling for him?” He was equably resigned to his lectures being sparsely attended because of their extreme technicality. One semester, unexpectedly many students turned up at the first lecture. He looked around the room in surprise and asked “What are you all doing here? I am not Bergson.” For those who were just there for the sake of doing a course and clocking up their attendance he quietly signed off their lecture books straight away, and told them not to worry about coming again. The few die-hards came for the sake of the logic. Leśniewski would enter the lecture room with a briefcase stuffed with papers, root around, find where he had got to and carry on, writing formulas and explaining how they were derived. When Quine visited some of these lectures, he was able to follow them despite knowing no Polish.