Walls or Borders

'Mending Wall' is primarily about walls or borders.  Walls separate people from each other.  They exclude people and injure harmonious relationship.  They represent lack of trust.  The speaker in the poem is of this opinion.  But the neighbour is of the view that walls are necessary to avoid disputes.  Where there are no physical demarcations, there is bound to be disputes as, for example, in the case of India China border or India Pakistan border.  Hence the argument, good fences make good neighbours.  But who are good neighbours?  They are ideally those who do not need a wall to live in harmony.  They live in mutual understanding, love and trust.  In that case a wall will be unnecessary.  Our society needs to grow into that consciousness.  We haven’t reached there yet.  Till that time, we may need walls to keep peace between us.  This argument probably solves the ambiguity in the poem regarding the need of walls.  Walls are not necessary in an ideal society.  But till we reach that goal, we may need them.

Walls as Rules and Laws

The same argument can be extended and we can compare walls to rules and laws.  An ideal society is one in which rules and laws are unnecessary.  If people do not violate other people’s freedom or if they do not intend any harm to others, we do not need strict rules and stringent enforcement of those rules.

When Bible says you are not under the law, but under grace, it means this.  Laws are for immature people.  When they are able to grow beyond their immaturity, they will not violate anyone’s rights even if there is no law to prevent it.   Until our society grows to that maturity, laws may be necessary.  Same is the argument here; walls are unnecessary, but not until we are all able to live harmoniously.

Tradition
The neighbour repeats the old dictum “good fences make good neighbours” just out of habit.  Old habits die hard.  When thoughtlessly we repeat some words or actions, they become a ritual.  The annual wall mending has also become such a ritual for the neighbour.  We do not think much about its function or use, we just do it because people do it.  This is the story of most rituals.  We will have to come out of the darkness of the stone age to come to a certain awareness and rationality.  But questioning traditions is a dangerous business.  Many reformers who had tried that had to pay with their lives.  Frost passes no judgement in the poem.  He just presents the issue.

Myth of Sisyphus
In Greek mythology, Sisyphus was punished to roll a huge stone up a hill only to roll down every time it reached near the top.  The repeated wall mending and the difficulty to make the stones stay on top of each other reminds the reader of this story.  The myth of Sisyphus has various interpretations.  One of them is the absurdity of life.  But as human beings we are forced to go on with the repetitive task, but as Albert Camus suggests, we must imagine Sisyphus happy, as "The struggle itself towards the heights is enough to fill a man's heart."  Probably Frost is mischievously (Spring is the mischief in me) suggesting that even if we find life absurd, we should derive some happiness from our efforts and at the same time be aware of the futility of our efforts.