What do the shadows symbolize in cartoon Looking Backward by Joseph Keppler?

"Looking Backward" is a political cartoon by Joseph Keppler, not a cartoon titled "Looking Backward" by Edward Bellamy, which is the book you are likely thinking of. The cartoon you're referring to is from the 1880s, and it is not specifically attributed to Joseph Keppler, though it was published in Puck Magazine which was under his direction.

However, the concept of shadows in political cartoons of that era are frequently used to represent:

* Oppression: Shadows are often used to depict the powerful or wealthy figures who cast a long shadow over the less fortunate. This can represent the oppressive nature of systems like monopolies, corruption, and exploitation.

* Ignorance: Shadows can also symbolize the lack of knowledge or understanding that is often present in those being exploited. This can be seen as a metaphorical barrier to progress and enlightenment.

* Fear and Injustice: The darkness of shadows can evoke a sense of fear and uncertainty, reflecting the anxieties of the working class under unjust systems.

While it is difficult to definitively determine the exact symbolism of the shadows in the specific cartoon you're asking about without seeing it, these general interpretations are common in political cartoons of the time.

If you can provide more context about the cartoon (e.g., its subject matter, the figures depicted, or the accompanying caption), I might be able to give a more specific interpretation.