Under representationalism, qualia-statements are equivalent to statements about how things appear (e.g., 'e has Q_{Rx ∧ Sq(x)}' is equivalent to 'e is an experience of something's looking red and square').
A shorthand way philosophers write complex ideas using letters and symbols; here it's condensing 'the quality of looking red and square' into a compact formula that's easier to work with logically.
Representationalism(Philosophy of mind; color experience)
The view that the phenomenal character of experience supervenes on (or is determined by) representational properties
qualia(The passage presents two competing definitions to contrast the views)
On the Cartesian picture: intrinsic qualities of inner ideas of which subjects are directly aware, necessarily shared by internal duplicates regardless of environment. On wide representationalism: representational contents of inner states whose nature is partly externally determined
Now notice that there are many entailment relations between qualia-statements—for example, ‘\(e\) has \(Q_{Rx \amp Sq(x)}\)’ entails ‘\(e\) has \(Q_{Rx}\)’, and ‘\(e\) has \(Q_{Rx \amp Tr(x) \amp By \amp Sq(y)}\)’ entails ‘\(e\) has \(Q_{Rx \amp Sq(y)}\)’, and so on. The orthodox representationalist and the sense-datum theorist have simple accounts of these entailments in terms of the structure of the objects of experiences (apparent structure, for the representationalist; actual structure, for