Ques­tions like: What is know­ing? Where are the lim­its of pre­dictabil­i­ty? Are there lim­its to causal­i­ty? are dealt with in this dis­cus­sion with Anton Zeilinger. He talks about sur­pris­es, the applic­a­bil­i­ty of his research in quan­tum com­put­ers, and, among oth­er things, sug­gests to make teach­ers the best-paid seg­ment of soci­ety.