I want to know the answer to the following question:
What did Hume say can't be rationally justified?
All the background I'm provided with is that "Most of Hume's followers have disagreed with his conclusion that belief in an external world is rationally unjustifiable, contending that Hume's own principles implicitly contained the rational justification for such a belief, that is, beyond being content to let the issue rest on human instinct, custom and habit.". Is that enough to answer the question?
Answer: yes