William Blake’s “London” is a poem about contemporary life at the time as it is characterized by certain forces that affect social, intellectual and spiritual life. The city, London, is used to represent these forces, many of which are institutional. Urbanization, to use a modern term, is part of what Blake is criticizing in this poem about the dehumanizing influence of a prevailing commercial and religious ethos that seeks to shape individuals into conformity.
This is a poem about ideology. Ideology, in “London,” is evoked in the phrase, “mind forg’d manacles.” This phrase speaks to the notion that the institutions governing behavior and defining social norms come to exist in the minds of the citizens of the city. People’s thinking is controlled, to a significant extent, for Blake, by the dictates of the Church and the State.
In every cry of every Man,
In every Infants cry of fear,
In every voice: in every ban,
The mind-forg'd manacles I hear
The suffering that results from the imposition of the collectively defined ideology relates closely to commerce and economically driven constraints.
Forced to sell her body to make money, ostensibly to simply survive, “the youthful Harlots curse/Blasts the new-born Infants tear/And blights with plagues the Marriage hearse.” Thus the life of the prostitute is rendered miserable by the need for money while sexually transmitted disease in turn plagues the new marriage of those who are lucky enough to be in the position to marry.
There is a cycle at work, suggested in the last stanza. This cycle knits together the misery of the innocent (the infant, the new marriage) along with the “experienced,” as it were. The Church in the poem does not bring light but is described as “blackening” and so can be seen to take part also in this fusion or inversion of innocence and experience.
The professions mentioned in the poem, from soldier to chimney sweep, are depicted negatively. Manacles of economic origin thus parallel those of the mind. The idea that animates the city – an idea relating to commerce and economic vigor – is ultimately connected to an idea of spiritual death.
So, again, the themes of the poem relate to the ways that, for Blake, the doctrines of commerce that define London can function to constrain or imprison individuals into roles that may be rigid, unpleasant, and/or harmful to the life of the spirit. In some ways the citizens are enslaved to a system of commerce wherein there is no chance for joy or innocence.