Given two propositions S1 and S2 both of which say that some gradable parameter P holds to a degree D, then a proportional comparison of them says that if D1 varies gradually in one direction, D2 varies proportionately.

In , P1 is the hardness of my work, P2 is my sickness, D1 varies upwards on P1, D2 varies in the same sense on P2, and the construction S1 S2 says that D2 depends on D1.