Kurt Gödel

Kurt Gödel did something almost no thinker ever manages: he found the edge of logic itself and showed us it was there. Ranked alongside Aristotle and Frege among the greatest logicians in history, he proved in 1931 his incompleteness theorems, the stunning result that any formal system strong enough to describe arithmetic must contain true statements it can never prove, and cannot even prove its own consistency. To do it he invented Gödel numbering, coding the language of mathematics into ordinary whole numbers. Later he showed that neither the axiom of choice nor the continuum hypothesis could be disproved from standard set theory.

His Sun sat in Taurus, and there is the foundation-builder, the sign that lays down solid ground and holds an opinion the universe itself could not beg him to change. That Taurean stubbornness became a mathematical virtue: he built bedrock and refused to be moved from it. His Moon in Gemini gave the other half, the restless, fact-hungry, endlessly analytical mind that lives in symbols and words, forever turning ideas over. Earth and air, the immovable and the ceaselessly thinking. Between them he mapped the limits of reason with a precision the twentieth century never forgot.