Rav Yisrael Salanter, the founder of the Mussar movement, was once giving a Shiur in Gemara, and as he was delivering the lecture, a student asked him a question. The question was very strong, and negated the premise of the entire Torah thought Rav Yisrael was trying to develop. Rav Yisrael thought for a few minutes, and then he looked at the student who asked the question and told him, “You are right. I have no answer to that question.” He then closed the Gemara and ended the Shiur.

After the Shiur he came over to his students and told them, “You should know that while I was thinking about that question, I had five different answers that I could have given. However, I didn’t feel that they were completely Emes, they were not entirely ‘true’. I thought to myself that it might be worth it to say one of these answers just to save my Shiur, but to do something unethical, when I have devoted my life to promote Mussar, would not be very ethical!”