PROPOSITION XC.

Sensile perceptions, though they cannot be, properly speaking, false, may be called false analogically.

In the origin of human thought, the senses stand midway between the Intellect and Being; so that the saying is true, There is nothing in the intellect, that has not first passed through the senses. Consequently, these latter stand in a twofold relation; viz, in their relation to the intellect, and in their relation to Being. Considered in their relation to the intellect, they present themselves as psychological entities, or as lenses which present the sensible object; in other words, as representative or, (to speak more accurately), presentative. Considered in their relation to Being, they appear either as pure sensible perceptions or as sensible judgments. It will be well to consider them under each of these four aspects separately.

i. A sensible perception is a real Being and has a physical entity of its own and, therefore, as such, is intelligible and a proper object of the intellect. Under this form, a sensible perception shows itself before the intellect as a certain definite modification of the soul; and, as such, it can never, in any sense of the term whatsoever, be false. For, however disordered the perception may be presentatively, there can be no doubt as to the subjective impression. Thus, for instance, a patient in a fever may mistake milk for quinine; but it is certain that he has felt the sensation of bitterness. It is not, of course, a question now about fancies, but about real sensations; and these are, -- must be, -- without exception, subjectively true.

ii. But, in the second place, these sensile perceptions come before the mind as presentative of their sensible object; so that, by reason of their presence, the intellect is determined to the cognition of that entity so presented. Here there is room for a species of Falsity. For the sensile perception, owing to a variety of causes, may be so indistinct as to occasion the formation of a false Judgment. Thus, for instance, in an example already adduced, owing to the mist, the impression on the sense of sight was so confused as to induce the intellect to conclude that what was really a man, was an ox. So, again, the patient was led, by the deceptive sensation in his fevered tongue, to form the erroneous Judgment that the proferred cup of milk was quinine. In this way, a sensile perception may justly be called false according to analogy of attribution of the first class; forasmuch as, though not false itself; it becomes the occasion or cause of a false Judgment in the mind.

iii. A sensile perception may be considered in relation to Being; in that it is, after its own fashion, itself presentative. In this respect it follows the analogy of intellectual presentation; and, as a simple Apprehension of the intellect, is always true and, never can be false, for reasons already stated; so, a pure perception of the senses can never be called, even analogically, false in itself, though it may be called analogically false, as inducing the cogitative force (vis cogitativa) to form a false sensile Judgment. Such Falsity, again, would be predicated analogically of the simple sensile perception, according to the analogy of attribution of the first class. iv. Sensile perception, as representative of its object, may assume the shape of a quasijudgment. This, in animals, would be purely instinctive, and proceeds from its estimative force; but in man it is more or less combined with intellectual activity. Accordingly, a name is given to this faculty in man, which is proper to him. So far as the intellectual element is concerned, the Truth or Falsity would be predicated univocally. But the question at present is, touching that faculty of purely sensile judgment in all animals, which is eminently possessed by man. In such judgments can there be Falsity? If so, in what sense? Here it is necessary to introduce the division, already given in an earlier part, of the objects of sense. There is, then, first of all, the proper object of each separate sense. Then there is the proper object common to more than one sense, such as form, magnitude, distance, and the like. Lastly, there is the accidental object, which is the subject of the sensible accidents. Thus the sight perceives colour, as its special object; form, as an object common to it with the sense of touch; the man, whose colour and magnitude it perceives, becomes its object accidentally, and only so far forth as he is the one subject of the sensile accidents. Following this division, it appears (a) that a sensile Judgment concerning the proper separate object of any given sense is, under normal conditions, invariably true; becanse it is the natural act of that sense, and nature never fails in things necessary. The words, under normal conditions, have been advisedly added; because any lesion or defect of the organ on the one hand, or a failure in the due presentation of the object -- ineluding external impediments of whatever kind -- on the other, might induce a wrong Judgment concerning even the proper separate object. Thus, for instance, the eye might judge the blues in a painting to be greens; if the picture were examined by gaslight. Here the subjective sensation would be true, because the yellow light of the gas on the blue produces really and truly the sensile impression of green; but the Judgment would be wrong, that should attribute this colour to the painting. (b) A sensile Judgment concerning the proper object common to more senses than one, is liable to error. Thus, distance is common to eye, ear, and in some degree, touch. Now, it is not an uncommon thing, on first waking, when the faculties are not as yet in full activity, to see some piece of furniture in the room close up by the bedside: whereas it is really at an appreciable distance. So again, in the twilight, a gate has seemed to be close in front of one; whereas it was really yards off. In some of these instances it may be, that the imagination plays its role; still, making all reasonable deductions on this score, it seems to be little short of certain, that the eye grows to the accurate measure of distance, by habituation, and study of relations between objects. That the ear likewise may be deceived as to the distance of sounds, is sufficiently proved by the tricks of the ventriloquist. It is for this reason, doubtless, that such accidents are appointed to be the object of more than one sense; in order that the perceptions of various senses may, so to speak, correct each other. Hence, too, the necessity of the common sense and of the estimative faculty in animals. (c) A sensile Judgment is most especially liable to error touching the accidental objects of sense; because directly they are beyond its reach, and are only revealed to it as the common subject of those sensile accidents which are its proper object.^{1}

Thus, then, in these two last species of sensile Judgments, there may be Falsity; but of what kind? Certainly, it cannot be predicated of them univocally; for Falsity is proper to the intellect. It is, therefore, predicated of them according to analogy of proportion.

{1} Vide D. Thom., De Verit. Q. I, a. II, c.; 1ae xvii, 2, c., et ad 1m.