[P33: When we love a thing like ourselves, we strive, as far as we can, to bring it about that it loves us in return.

Dem.: As far as we can, we strive to imagine, above all others, the thing we love (by P12). Therefore, if a thing is like us, we shall strive to affect it with Joy above all others (by P29), or we shall strive, as far as we can, to bring it about that the thing we love is affected with Joy, accompanied by the idea of ourselves {as cause}, i.e. (by P13 S), that it loves us in return, q.e.d.