Extraordinary claims require extraordinary evidence. — Carl Sagan | Printable Wall Art

“Extraordinary claims require extraordinary evidence.”

Words by Carl Sagan (1934-1996) — American astronomer and science communicator.

About this quote

This phrase means that the more surprising or unlikely an assertion is, the stronger the proof must be before we accept it as true. Everyday statements need only simple proof, but ideas that challenge established knowledge require robust, unquestionable data. It promotes critical thinking and scientific scepticism, urging us to measure our belief against the quality of the facts provided.

Carl Sagan popularised this formulation in his 1980 television series Cosmos and its accompanying book. While similar principles were expressed earlier by thinkers like Pierre-Simon Laplace and Marcello Truzzi, Sagan made the exact phrasing a cornerstone of modern scientific scepticism.

People often hang this quote in a study, library, or classroom to encourage rigorous thought and clear logic.

What you get

An instant digital download. Choose your design and size at checkout — 19 typographic designs and 8 print sizes are available for this quote.

• Print-ready PDF with fully embedded vector type — sharp at any scale
• Exact trim size, no cropping required
• Print at home, at a local print shop, or upload to an online printer
• Instant download — no physical item is shipped

Sizes available

5" x 7" · 8" x 10" · 11" x 14" · 12" x 16" · 16" x 20" · 18" x 24" · 24" x 36" · A4 (21 x 29.7 cm)

Designs available

Atelier Serif · Quiet Garamond · Studio Left · Gallery Rule · Midnight Serif · Editorial Left Serif · Modern Sans Calm · Letterpress Caps · Poster Condensed · Script Whisper · Manuscript Italic · Asymmetric Left · Minimal Unsigned · Charcoal Sans · Gallery Frame · Soft Serif Right · Statement Serif · Night Script · Tracked Caps Unsigned

Digital product. Colours may vary slightly between screens and printers. Frames and props are not included.