We must now consider how the passions differ from one another: and under this head there are four points of inquiry:

A[1] Whether the passions of the concupiscible part are different from those of the irascible part?

A[2] Whether the contrariety of passions in the irascible part is based on the contrariety of good and evil?

A[3] Whether there is any passion that has no contrary?

A[4] Whether, in the same power, there are any passions, differing in species, but not contrary to one another?