Full Idea
Bradley argued that we cannot conceive of primary qualities except as attached to secondary qualities.
Clarification
Meaning that reality always boils down to a set of experiences
Gist of Idea
We only conceive of primary qualities as attached to secondary qualities
Source
Roger Scruton (Modern Philosophy:introduction and survey [1994], 10.1)
Book Reference
Scruton,Roger: 'Modern Philosophy: introduction and survey' [Sinclair-Stevenson 1994], p.114