The Sagan Information Scale

In 1973, Carl Sagan proposed a radical complement to the famous Kardashev Scale. While Kardashev measured civilizations by energy consumption, Sagan introduced a second dimension: the total amount of information a civilization stores and processes. He created an alphabetical scale from Type A (10⁶ bits) to Type Z (10³¹ bits), offering a way to classify civilizations by knowledge rather than power alone.
This book provides the most comprehensive exploration of the Sagan Information Scale available. It traces the scale's origins in Sagan's groundbreaking book The Cosmic Connection, explains how the alphabetical system works, and assesses where humanity currently stands - having jumped from approximately Type H in 1973 to Type S by 2024-2025, an eleven-category leap in just fifty years. Along the way, it connects the scale to some of the deepest ideas in modern physics: the thermodynamics of information, Maxwell's demon, Landauer's limit on the energy cost of computation, Seth Lloyd's "ultimate laptop," and Freeman Dyson's vision of eternal intelligence.
Equally important, this volume confronts the scale's limitations with honesty. In an age of big data, social media, and artificial intelligence, the distinction between raw data and genuine knowledge has become increasingly difficult to draw. The book examines whether AI-generated content counts as "unique information" and why the Sagan scale, while powerful, cannot stand alone. It must be integrated with the energy, spatial, tool-based, and inward lenses explored in the earlier volumes of this series.
Part of the Civilization Scales Series, this book adds a fifth essential lens to our understanding of civilizational advancement - one that may prove especially relevant in an era defined by the exponential growth of information.
For readers interested in Carl Sagan, the physics of information, SETI, artificial intelligence, and the future of knowledge itself.