The correct answer is 4. No, because he digresses into another topic and does not address historical knowledge.
Explanation
At the beginning of the paragraph, the author announces the sentence "In no other department is a thorough knowledge of history so important as a philosophy". However, nowhere in the paragraph does he develop this idea, on the contrary, he mentions other issues such as the relationship between philosophy and other fields such as exact inqury, the arts (as he mentioned in "on the other hand, in touch with exact inquiry, while, on the other, it has a certain relationship with art"), natural sciences, metaphysical principles, among others. From the above, it can be inferred that the correct answer is 4. No, because he digresses into another topic and does not address historical knowledge.
