Final answer:
The speaker from 'Mending Wall' questions the purpose of walls, suggesting they should only be built with a clear understanding of what they separate and why.
Step-by-step explanation:
In Mending Wall, the speaker casts doubt on the necessity of barriers by stating, "Before I built a wall I'd ask to know What I was walling in or walling out, And to whom I was like to give offence." This indicates the speaker's contemplative nature, as he explores the consequences and intentions behind constructing a divider. The reflection on building a wall conveys a deeper philosophical questioning of the purposes and effects of setting boundaries, alluding to a broader commentary on human relationships and separateness.