Full Idea
For functionalism mental states as roles are second-order properties that have to be realised in various ways in first-order physical properties.
Gist of Idea
Mental states as functions are second-order properties, realised by first-order physical properties
Source
Pascal Engel (Truth [2002], §3.3)
Book Reference
Engel,Pascal: 'Truth' [Acumen 2002], p.86
A Reaction
I take that to be properties-of-properties, as in 'bright red' or 'poignantly beautiful'. I am inclined to think (with Edelman) that mind is a process, not a property.