Abstract: Properties of phenomena are, like Locke's secondary qualities, relational; and, like Locke's primary qualities, objective and attributable by science. These ‘primary’ qualities include spatial and space-filling, i.e. geometrical and dynamical, features, and matter is constituted by a conflict of forces. Kant substitutes impenetrability for solidity, thereby substituting relational powers for intrinsic properties. His argument bears on our contemporary view that powers are contingently grounded in intrinsic properties, a view that must concede the possibility of solid things being penetrable, and acknowledge, for different reasons, the unknowability of those intrinsic properties. Kant's ‘primary’ qualities anticipate Faraday's field theory, and show, pace Evans and Bennett, that qualities do not need to be intrinsic if they are to be scientific and objective.

Keywords: Faraday, field theory, force, impenetrability, primary quality, properties, qualities, secondary quality, solidity, space-filling,