Eigen's paradox

Eigen's paradox is the chicken-and-egg problem at the heart of the origin of life: the information required to build a high-fidelity molecular replicator exceeds the amount of information that can be maintained without one. Longer genomes encode more functional complexity, but longer genomes also require lower error rates to avoid crossing the error threshold. High-fidelity replication, in turn, requires enzymatic machinery — encoded in the very genome that needs protecting.

Manfred Eigen identified this paradox as a fundamental constraint on the prebiotic evolution of information-bearing molecules. The paradox implies that life could not have emerged through a single, linear increase in complexity. Instead, the transition from non-life to life required a cooperative network — such as the hypercycle — in which the replication machinery was distributed across multiple short sequences, each below its individual error threshold, but collectively encoding enough information to produce the next generation.

The paradox is not merely a historical curiosity. It reappears in any system where information must be used to improve its own copying: digital evolution, machine learning, and even the design of error-correcting codes face structurally analogous constraints.