Richard Dedekind

Mathematics German 1831 – 1916 399 quotes

A German mathematician who made important contributions to abstract algebra, particularly in algebraic number theory.

Most quoted

"If all points of the straight line fall into two classes such that every point of the first class lies to the left of every point of the second class, then there exists one and only one point which produces this division of all points into two classes, this severing of the straight line into two portions."

— from Stetigkeit und irrationale Zahlen, 1872

"The continuity of the domain of real numbers is the property that if all its elements are divided into two classes, such that every element of the first class is less than every element of the second class, then there exists one and only one number which produces this division."

— from Stetigkeit und irrationale Zahlen, 1872

"The way in which the irrational numbers are usually introduced is based directly upon the conception of extensive magnitudes—which itself is nowhere carefully defined—and explains number as the result of measuring such a magnitude by another of the same kind."

— from Stetigkeit und irrationale Zahlen, 1872

All quotes by Richard Dedekind (399)

The foundation of mathematics must be built on solid logical principles.

Was sind und was sollen die Zahlen? 1888

The concept of a ring is a generalization of the concept of integers.

Essays on the Theory of Numbers

The beauty of mathematics lies in its logical structure.

Essays on the Theory of Numbers

What is provable is not always true.

Letter to Heinrich Weber

I see no reason why the concept of number should be restricted to the rational numbers.

Letter to Rudolf Lipschitz

The numbers are free creations of the human mind.

Was sind und was sollen die Zahlen? 1888

I have often heard that mathematics is the queen of the sciences, but I have never heard that it is the handmaiden of the sciences.

Unknown private writing

A definition is good if it is useful.

Letter to a student

I believe that the true nature of mathematics is to be found in its abstractness.

Letter to a colleague

My work is not for the faint of heart.

Letter to a friend

I am a mathematician, not a philosopher.

Letter to a philosopher

The beauty of mathematics lies in its simplicity.

Unknown private writing

I have always been fascinated by the concept of infinity.

Letter to Georg Cantor

The foundations of mathematics are not as solid as one might think.

Letter to a colleague

I strive for clarity and rigor in all my work.

Unknown private writing

Mathematics is a language, and I am trying to speak it fluently.

Letter to a student

The joy of discovery is what drives me.

Diary entry

I am not afraid to challenge established ideas.

Letter to a mentor

The real numbers are a continuous domain.

Letter to Rudolf Lipschitz

My aim is to make mathematics more accessible.

Unknown private writing