The central themes in the Songs of Experience include disillusionment with the new industrialised society and lack of humanity. Whereas the Songs of Innocence feature personas who are optimistic in tone and reflect the values held by the Romantic poets, the personas in the Songs of Experience only notice the negative aspects of their society.
The poem "London" highlights all of the negative elements of city life during the Romantic period. It emphasises a lack of humanity by indicating that the people do not care for each other. This lack of concern is particularly evident in the behaviour of institutions of the day, such as the government and the church.
Many of Blake's poems present the idea of innocence via the image of the child. In the Songs of Innocence, the child is taken care of, valued and allowed to grow and flourish. In contrast, the child in the Songs of Experience has a more realistic view of the world. They are forgotten, overworked (like the Chimney Sweep) and undervalued. The symbolism of the coffin in "The Chimney Sweep" is particularly strong in conveying this idea. The coffin and reference to black suggest that the children had symbolically died, no longer being valued in society, and had to be rescued.
Another key idea represented in this poem is that people had stopped caring for nature and wear instead attempting to conquer it. This is evident in lines such as "near where the charter'd Thames does flow." This implies that people had tried to dominate nature to the point of owning a river. This change from the agrarian society to the industrialised society and its change of values had a widespread impact on the natural world. It seemed, both literally and metaphorically, to sicken and die. This idea is also represented in "The Sick Rose" where the rose represents the natural world which, through the action of man, has sickened and will eventually die.