- Lived:
- 1901–1983 · Warsaw, Poland; Berkeley, California
- Tradition:
- Polish school of logic; mathematical logic and the birth of formal semantics
- The Big Idea:
- Truth — the oldest and slipperiest word in philosophy — can be defined with mathematical exactness, but only from outside the language being talked about; no language rich enough to matter can define truth for itself.
- In their words:
- "'Snow is white' is true if, and only if, snow is white."
- If you remember one thing:
- A high-school teacher in Warsaw, denied a professorship by prejudice, tamed the ancient liar paradox and gave truth a mathematical spine — and his definition now runs silently under every database query and compiler check on earth.