The last portion of the novel, after the Sphere ridicules the Square and leaves him, is again highly political, and deals with the justice system in the basically totalitarian state that the Square and his family live in. In order to maintain complete control over the citizens, the government of Flatland outlaws the use of color or "chromatic expression," and also ends up outlawing the discussion or mention of dimensions beyond the second, which carries the death penalty for some.

The Square is not killed, but he is imprisoned for continuing to discuss his ideas about other dimensions (Abbott, 1884). This mirrors the persecution that many scientific figures suffered at the hands of various governments and religious institutions (particularly the Catholic Church) for spreading knowledge that they had verified through repeated observation or mental exercises. In fact, both the mathematics and the politics that appear in Flatland have continued to influence political thinking and evaluation. Some of the mathematics of the book are shown to correlate to certain political aspects of the book, making the work perhaps more profound than Abbott ever intended (McCubbins & Schwartz, 1985). Certainly, the entire novel pushes for freedom, justice, and equality, both by satirizing certain social institutions and beliefs and by promoting the free and rigorous use of logical examination as a way of discovering, learning, and truly knowing things about the world we live in. The alternative that Flatland shows is a world full of people that do not really listen to or respect each other, and they often show as little regard for the realities of physical and theoretical truth.

Though this book is almost one hundred and thirty years old, it is still very useful today. It can be read as an introductory text to certain mathematical and philosophical concepts, a historical document showing the opinions and mores of an incredibly restrictive society and the response that this restrictiveness inspired in certain individuals, and a manifesto for social justice. It is still meaningful in all of these ways, and the popularity that the book has enjoyed over the past century is a good indicator that it will remain popular for centuries to come.