Professor: It has been argued that freedom of thought is a precondition for intellectual progress, because freedom of thought allows thinkers to pursue their ideas, regardless of whom these ideas offend, in whatever direction they lead. However, it is clear that one must mine the full implications of interrelated ideas to make intellectual progress, and for this, thinkers need intellectual discipline. Ttherefore, this argument for freedom of thought fails.
In societies that protect freedom of thought, thinkers invariably lack intellectual discipline is an assumption required by the argument for the conclusion drawn by the professor.