Full Idea
The essence of gold is what constitutes it and gives it the sensible qualities which let us recognize it and which make its nominal definition; but if we could explain this structure or inner constitution we would possess the real, causal definition.
Gist of Idea
A nominal definition is of the qualities, but the real definition is of the essential inner structure
Source
Gottfried Leibniz (New Essays on Human Understanding [1704], 3.03)
Book Reference
Leibniz,Gottfried: 'New Essays on Human Understanding', ed/tr. Remnant/Bennett [CUP 1996], p.294
A Reaction
This is the view which I am championing, particularly in the role of explanation in the whole game. Explanation and understanding are the hallmarks of the discovery of a real essence. However, a falsehood may explain things well. Tricky.
Related Ideas
Idea 12975 We have a distinct idea of gold, to define it, but not a perfect idea, to understand it [Leibniz]
Idea 12977 We will only connect our various definitions of gold when we understand it more deeply [Leibniz]