Passage Summary: Some people say you need total freedom to think well, but a professor argues that because you actually need strict discipline to follow ideas to their end, the freedom argument is wrong.

Conclusion: The argument that freedom of thought is a necessary condition for intellectual progress is incorrect.

Reasoning: Intellectual progress requires intellectual discipline to fully explore the implications of ideas, which contradicts or replaces the need for total freedom of thought.

Analysis: The professor's argument contains a significant gap: it assumes that the need for 'intellectual discipline' somehow invalidates the need for 'freedom of thought.' To make this conclusion follow logically, we must assume that these two things are incompatible or that discipline is the only thing that truly matters for progress. A sufficient assumption will bridge this gap by stating that if discipline is required, then the freedom-based argument must be false. Look for an answer that creates a 'one or the other' relationship between discipline and the freedom of thought argument.