Why do we believe more than we can prove? Why does memory deceive us? Why do the most sophisticated artificial intelligence systems "hallucinate" false information?

In Homo Credens, Boris Kriger reveals a profound truth about the nature of complex minds: any sufficiently complex system—whether human brain, animal cognition, or artificial intelligence—must believe far more than it can verify. This is not a limitation to be overcome but an architecture to be understood.

Drawing on three research papers, Kriger shows how the complexity-credence trade-off shapes everything from memory and perception to reasoning and artificial intelligence. As systems become more complex, their capacity to verify propositions grows linearly while the space of propositions they must consider grows exponentially. The inevitable result: complex systems must commit to beliefs without verification.

The implications extend from philosophy to practical technology. Complete rationality is not difficult but impossible. Even quantum computers cannot escape the complexity-credence trade-off. AI hallucination cannot be eliminated without eliminating the generative capacity that makes AI useful.

We have long called ourselves Homo sapiens—the knowing species. This book proposes a more accurate name: Homo Credens—the believing species. We are not knowers who occasionally trust but trusters who occasionally verify. And in understanding this, we take the first step toward believing well.

A profound reimagining of the human mind and its place in a universe of complex systems, Homo Credens will change how you think about knowledge, memory, rationality, and what it means to believe.