Ignoramus et ignorabimus

Ignoramus et ignorabimus

Emil du Bois-Reymond (1818–1896), promulgator of the maxim ignoramus et ignorabimus.

The Latin maxim ignoramus et ignorabimus, meaning "we do not know and will not know", stood for a position on the limits of scientific knowledge, in the thought of the nineteenth century. It was given credibility by Emil du Bois-Reymond, a German physiologist, in his Über die Grenzen des Naturerkennens ("On the limits of our understanding of nature") of 1872.


  • Hilbert's reaction 1
  • Seven World Riddles 2
  • Sociological responses 3
  • See also 4
  • Notes 5

Hilbert's reaction

On the 8th of September 1930, the mathematician David Hilbert pronounced his disagreement in a celebrated address to the Society of German Scientists and Physicians, in Königsberg:[1]

Previously, at the International Congress of Mathematicians in 1900 in Paris he said: "In mathematics there is no ignorabimus."[2]

Hilbert worked with other formalists to establish concrete foundations for mathematics in the early 20th century. However, Gödel's incompleteness theorems showed in 1931 that no finite system of axioms, if complex enough to express our usual arithmetic, could ever fulfill the goals of Hilbert's program, demonstrating many of Hilbert's aims impossible, and specifying limits on most axiomatic systems.

David Hilbert replied, Wir müssen wissen — wir werden wissen! (We must know — we will know!)

Seven World Riddles

Emil du Bois-Reymond used ignoramus et ignorabimus in discussing what he called seven "world riddles", in a famous 1880 speech before the Berlin Academy of Sciences.

He outlined seven "world riddles", of which three, he declared, neither science nor philosophy could ever explain, because they are "transcendent". Of the riddles, he considered the following transcendental and declared of them ignoramus et ignorabimus:[3] "1. the ultimate nature of matter and force, 2. the origin of motion, ... 5. the origin of simple sensations, a quite transcendent question."

Sociological responses

The sociologist Wolf Lepenies has discussed the ignorabimus with a view that du Bois-Reymond was not really retreating in his claims for science and its reach:[4]

— it is in fact an incredibly self-confident support for scientific hubris masked as modesty —

This is in a discussion of

See also


  1. ^ Hilbert, David, audio address, transcription and English translation.
  2. ^
  3. ^ William E. Leverette Jr., E. L. Youmans' Crusade for Scientific Autonomy and Respectability, American Quarterly, Vol. 17, No. 1. (Spring, 1965), pg. 21.
  4. ^