Unreal numbers
Summary
Unreal Numbers is a Substack essay that traces how numbers—from natural numbers to real numbers—can be constructed from first principles and discusses the limitations of computability. It covers Peano arithmetic, ordinals, rationals, and Dedekind cuts, arguing that most real numbers are uncomputable and highlighting the cardinality gap between 𝔑 and ℝ. The piece blends formal definitions with accessible explanations and points to related posts in the series.