It is because I feel myself to be substance-that is to say, permanent in the midst of my changes-that I attribute substantiality to those agents exterior to me, which are also permanent in the midst of their changes-just as the concept of force is born of my sensation of personal effort in putting a thing in motion.
Substantzia sentitzen naizelako, hau da, neure aldaketen artean iraunkor, nigandik kanpoko agenteei ere substantzialtasuna esleitzen diet, beren aldaketen artean, iraun dirautenei.