Tertullian

“ In this way, then, there cannot occur an illusion in our senses without an adequate cause. Now if special causes, (such as we have indicated,) mislead our senses and (through our senses) our opinions also, then we must no longer ascribe the deception to the senses, which follow the specific causes of the illusion, nor to the opinions we form; for these are occasioned and controlled by our senses, which only follow the causes. Persons who are afflicted with madness or insanity, mistake one object for another. ”

“ All the senses, therefore, are disordered occasionally, or imposed upon, but only in such a way as to be quite free of any fault in their own natural functions. But further still, not even against the specific causes and conditions themselves must we lay an indictment of deception. For, since these physical aberrations happen for stated reasons, the reasons do not deserve to be regarded as deceptions. Whatever ought to occur in a certain manner is not a deception. ”

“ Hence we are bound most certainly to claim for the senses truth, and fidelity, and integrity, seeing that they never render any other account of their impressions than is enjoined on them by the specific causes or conditions which in all cases produce that discrepancy which appears between the report of the senses and the reality of the objects. What mean you, then, O most insolent Academy? You overthrow the entire condition of human life; you disturb the whole order of nature ”

“ The delicacy of the substance or medium which forms a mirror by means of its luminosity, according as it is struck or shaken, by the vibration actually destroys the appearance of the straightness of a right line. ”