Full Idea
Though we see the yellow, and upon trial find the weight, malleableness, fusibility and fixedness of gold, yet because no one of these has evident dependence or necessary connexion with the other, we cannot know if four are there, the fifth will be also.
Gist of Idea
We know five properties of gold, but cannot use four of them to predict the fifth one
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 4.03.14)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.546
A Reaction
Thus it is that knowledge of necessary properties cannot lead us to knowledge of essence, because explanatory dependence is in the opposite direction. The point of knowing essences is to gain increased powers of prediction.
Related Idea
Idea 15297 We can infer a new property of a thing from its other properties, via its essential nature [Harré/Madden]