In general, though philosophy seeks the cause of perceptible things, we have given this up (for we say nothing of the cause from which change takes its start), but while we fancy we are stating the substance of perceptible things, we assert the existence of a second class of substances, while our account of the way in which they are the substances of perceptible things is empty talk;
25) Nahiz eta, azken batean, Jakinduriak fenomenoen kausa bilatzen duen, ez gara honetaz arduratu (ezer esaten ez baitugu aldaketaren printzipioaren sorburuaren kausaz), eta fenomenoen substantzia esaten dugulakoan, bestelako substantziak daudela esaten dugu.