Single Idea 22429

[catalogued under 12. Knowledge Sources / B. Perception / 2. Qualities in Perception / b. Primary/secondary]

Full Idea

At the end [of the three stages of objectivity] the secondary qualities drop out of our picture of the external world, and the underlyiing primary qualities such as shape, size, weight, and motion are thought of structurally.

Gist of Idea

We achieve objectivity by dropping secondary qualities, to focus on structural primary qualities

Source

Thomas Nagel (The View from Nowhere [1986], II)

Book Reference

Nagel,Thomas: 'The View from Nowhere' [OUP 1989], p.14


A Reaction

This is the orthodox view for realists about the external world, and I largely agree. The only problem I see is that secondary qualities contain information, such as the colour of rotting fruit - but then colour is not an essential feature of rot.

Related Idea

Idea 22354 Things cause perceptions, properties have other effects, hence we reach a 'view from nowhere' [Nagel, by Reiss/Sprenger]