Directions: For the given question, select one entry for the blank from the given choices, to best complete the text.

For the past century or so, philosophy has primarily entailed ___________ deep truths about the nature of human existence - questions about reason, knowledge, values, and free will. Philosophy can seem like a lonely ivory-tower vigil, but the old school holds that sitting and thinking is still the best way to do it.

(1) Incorrect; the clue comes from 'philosophy can seem like a lonely ivory-tower vigil'. Words that denote a lonely vigil are needed. (2) Incorrect; because philosophy is a 'lonely vigil' and thinking is anyways a solitary pursuit, words that denote this state of mind are needed. (3) Incorrect; nothing in the passage suggests philosophy being hard to understand, which is what esoteric would imply. (4) Incorrect; reflections is correct, but 'altruism' does not fit the passage. (5) Correct; because philosophy is a lonely vigil and entails sitting and thinking, which is also a solitary pursuit, the option neatly sums up the effort required.