Full Idea
The essence of a circle consists in the equality of all lines drawn from its centre to its circumference.
Gist of Idea
The essence of a circle is the equality of its radii
Source
Gottfried Leibniz (Letters to Thomasius [1669], 1669)
Book Reference
Cover,J/O'Leary-Hawthorne,J: 'Substance and Individuation in Leibniz' [CUP 1999], p.24
A Reaction
Compare Locke in Idea 13431 and Spinoza in Idea 13073 on the essence of geometrical figures. A key question is whether the essence is in the simplest definition, or in a complex and wide-ranging account, e.g. including conic sections for circles.
Related Ideas
Idea 13431 A space between three lines is both the nominal and real essence of a triangle, the source of its properties [Locke]
Idea 13073 To understand the properties we must know the essence, as with a circle [Spinoza]