The affection of one of the senses induces the understanding to infer a cause of the effect, but, as a conclusion from the consequent to the reason is never certain, illusion, which is deception of the senses, is possible, and indeed often occurs, as was pointed out above.
Sentsu baten afekzioak kausatik efektura doan adimen-judizioa eragiten du; ordea, arrazoitutik arrazoira ondorioa ez baita inoiz ziurra, horrela ahalgarri da begitazio faltsua sentsuen engainu gisa eta sarritan erreala, gorago aditzera eman denez.