I went to a few job interviews during past weeks. Most interviewers asked me to tell about problems I had solved, and to suggest a solution to a problem they really needed to solve. Some though offered me to solve brain teasers — problems they (or others) invented to test candidates. I solved most, but I felt bad about it. I can imagine many bright candidates who would fail an interview because of brain teasers.

Brain teasers are wrong — that’s my gut feeling, but I had hard time finding an argument to support my gut feeling. Now I have one. Here is the story of a 250 years old job interview.

Yechezkel Landau, the rabbi of Prague in the second half of the 18th century and a famous Jewish scholar, applied for the post when he was only 41. Local Jewish intellectual elite gave him a tough examination on the jewish law. The candidate had to analyse and resolve difficult case studies, and provide rulings for complicated situations.

Rabbi Yechezkel answered all questions except for one. But though he failed to solve one particular riddle, he showed clearly that the riddle was not a real case but a thought-up one, with the sole purpose to humiliate the candidate.

Rabbi Yechezkel said that human wisdom is divine, and because it is divine it only acts in real, God-inspired, situations. When presented with an artificial problem, constructed by one human just to test another human, the wisest thought is no better than a random guess.

Brain teasers are bad for job interviews. They are no better than choosing a candidate by throwing a coin.

Rabbi Yechezkel got the job, by the way.