JMC : Logic and Mental Philosophy / by Charles Coppens, S.J.

Chapter II.
Sensitive and Rational Cognition.

159. In our treatise on Critical Logic we have devoted a whole chapter (Ch. III.) to the explanation of the means by which certainty is obtained, entering into considerable detail on the subject of sensitive and on that of rational cognition. We have now to examine the nature and the workings of those two faculties in themselves; and we, therefore, add in this place such further details as were omitted before because they did not affect the certainty of human knowledge.


160. Speaking in Critical Logic (Logic, No. 142) of the outward senses, we remarked: "Two very different questions present themselves on this subject: 1. How far is the testimony of our external senses reliable? 2 How do the senses work so as to give us reliable testimony?" We then examined the first question; we are now to present the Scholastic theory, which answers the second query.

161. How, then, is sense-perception effected, whether it be considered in man or in the irrational animal? All animals have at least the sense of touch; perfect animals have the same five outer senses as man: the sight, hearing, taste, smell, and touch; they have also the inner senses, viz.: the common sense, imagination, sensile memory, and power of appreciation (Logic, No. 102). These are not mere instruments of a most delicate structure, but they are living organs in which and by which the animal exercises its faculties. The purpose for which they are intended by the all-wise Creator is to enable the animal in different ways to acquire cognition of the material objects with which it comes into immediate or mediate contact. Now, cognition implies that an object impresses some likeness of itself upon the cognitive subject, and that the subject, reacting, expresses the object thus impressed, apprehending it vitally. Thus the cognitive subject perceives, not indeed a likeness of the object but, by means of the likeness, the object itself. This process is observed both in all sensitive and in our intellectual cognition.

162. Confining our attention, for the present, to sense-cognition, we notice two distinct steps in the act of perception. 1. The object perceived must act upon the subject perceiving, by impressing on it -- whether directly, as in touch, or through a medium, as in vision -- some likeness, image, or species of itself. This image is called by the Schoolmen the species impressed, species impressa. Hence it is clear that sense-cognition begins with the action of the object; and, as the object cannot give forth an image of what it is not, but only of what it is, therefore it tends essentially to beget true cognition in the subject.

2. The subject perceiving must not be merely passive; for then it could not be said to elicit the act of perception or sensation; it must, therefore, react vitally on the impression received. And since all cognition is an immanent act, the sentient subject must reproduce in itself a vital image of the object. This vital image is styled the species expressed, species expressa; and the subject's immanent act of forming this vital image is its apprehension or cognition of the object.

163. The species impressed and expressed in sense-perception are, of course, the images of material objects existing in the concrete. Those objects are directly perceived by sense; the species are no more noticed by the sentient subject than the picture formed on the retina of the eye is noticed by us in our acts of vision.

164. If it be asked where the sensation takes place, in the sense-organ, say the eye, or in the brain, we answer that both brain and eye and connecting nerves co-operate in the act of seeing; all these together constitute the complex organ of sight; but the act of seeing should be said to be accomplished in the eye, the act of hearing in the ear, etc.; for thus only can it be properly said that we see and hear the outward object, and not the image of the object, or a modification of our senses.

165. The imagination, on the contrary, does not act in the organ of the outer senses; but its organ is the brain. It exists in perfect animals, and may perhaps be wanting in lower species of sentient life, some of which appear to have no senses but those of touch and taste. The imagination is the faculty by which animals form to themselves organic images, called phantasms, either of sensible objects perceived, or, in man at least, of other objects never perceived. In the latter case the images result from the combination of former phantasms, which themselves have been ultimately derived from objects of sensation.

166. The sensile memory performs a threefold office: (a) It directly brings back former phantasms; (b) Indirectly -- i.e., through the phantasms reproduced -- it represents objects formerly perceived; (c) It represents them as having been formerly perceived.

167. There is one sensible power of cognition to which it was not necessary to advert in Critical Logic since it is not one of the means by which men acquire certainty; we mean the power of appreciation, the vis aestimativa, of the Schoolmen. It is the highest of merely organic faculties, because it approaches the nearest to the intellectual power of judgment. Its action consists in apprehending certain concrete relations which sensible objects bear to the sentient animal. By it the lamb, even the first time that it sees a wolf apprehends him as dangerous to itself; by it the bird apprehends a straw as just then suitable for its nest. Such apprehensions are often called sensible judgments. They differ from intellectual judgments: (a) In always dealing with concrete material things; (b) In apprehending by mere organic action the relations existing between such things and the animal subject; (c) In absolutely excluding all abstraction.

168. In connection with the imagination, referred to above, it is appropriate to give here a brief explanation both of dreams, which are chiefly the work of the imagination, and of sleep, which occasions dreams. Sleep is a natural interruption of the equilibrium between the various faculties of man; for we shall confine our remarks to the sleep of man. It arises from the exhaustion of the animal organism, and is ordained by nature to restore that organism to its former freshness. It differs from disease, which is an unnatural disturbance of the same equilibrium.

169. We should not, then, imagine that sleep is a cessation of vital action, but rather it is a special mode of vitality. In sleep, 1. All the vegetative powers continue to act, but more gently and with more uniform motion than before. 2. The action of the senses is more or less suspended. 3. The sensible appetites are much relaxed. 4. The intellect may act, but it is not fully conscious of its operations. 5. The will may act, but not freely; hence we are not accountable for its actions when we are fully asleep, and not fully accountable when we are half-asleep. Sleep is really a time of repairs to the body; during it the machinery of the organism is out of gear.

170. Dreams are series of phantasms, reproduced and combined anew by the fancy, accompanied at times by some intellectual activity, while the nerves of the body are relaxed in sleep. Dreams are often started by actual impressions on the slumbering senses -- for instance, by some sounds or feelings -- and they are greatly influenced by any abnormal condition of the nerves and the blood. Our phantasms are not isolated, but variously associated with each other by similarity, by congeniality, by having been formed contemporaneously, etc.; and thus, when one phantasm is aroused, others are thereby excited, whether we are awake or asleep. When awake, we can to a great extent regulate the workings of our imagination by our will, and we are inclined to do so in connection with our sense-perceptions; but when we are asleep, our fancy has full play, and may, for all we know, be constantly moving, though it may leave no traces of its vagaries. From the nature of dreams just explained it is evident how foolish it is to attach any signification to them as foretelling future events, unless on special occasions they should be preternaturally produced by Providence for worthy and important purposes.

171. Somnambulism is a dream giving rise to corresponding external actions. Somnambulists act outwardly in conformity with their imaginations, but in a strange manner. 1. They proceed as if they saw, while their eyes are closed or rigid; thus they will avoid obstacles in their way, yet they really do not see, but are guided by their mere imagining of the familiar places, and therefore they will strike against obstacles to which they are not accustomed. 2. They do bolder and sometimes more ingenious things than when awake; for they do not reflect on danger, and all their faculties are concentrated on one purpose. 3. On awaking, they have no recollection of their wanderings.

172. Phenomena similar to those of somnambulism are produced by the mesmeric sleep. Mesmer (A.D. 1733-1815) boasted of having invented an art of healing diseases by means of magnetism, which he excited by touching the sick with a firm will to restore their health. One of the means employed in that process is the artificial or magnetic sleep. Seeing that sleep is merely a natural disturbance of the vital powers, we find nothing astonishing in the production of an artificial sleep by natural means. Nor is it absurd to suppose that the mesmerizer may affect the slumbering faculties of the sleeper or medium, usually a nervous woman, and so influence her imagination as to direct, to some extent, her feelings and her outward motions. But the magnetizer cannot do this directly by his will or his intellect; these faculties are essentially incapable of acting outside of the soul, and the soul is not outside its living body.

173. Induction proves that the souls of men cannot, in our present condition, communicate or act upon each other except by means of the body, and therefore by means of matter. As long, therefore, as the effects claimed to be produced upon the medium can be the results of material influence, those effects may be natural; but many phenomena of mesmerism are beyond the reach of material causes, and therefore they are preternatural. For instance, it is claimed that the person magnetized may become possessed of new intellectual powers, such as mind-reading and the power of seeing what is beyond the reach of the senses; or the medium suddenly possesses knowledge of things never learned, as of the latent causes and the remedies of diseases, or exhibits familiarity with foreign languages, etc. It is the part of Philosophy to trace effects to adequate causes. Now, some of the effects attributed to mesmerism, when they are really such as they pretend to be and not mere jugglery, cannot have any adequate causes in man, but only in spirits distinct from the souls of all those visibly present on such occasions.

174. The same test will apply to the phenomena of spiritism; namely, all clear exhibition of knowledge or intellectual action must be ascribed to an intellect as its source. If this cannot be the intellect of living men, then the effects must be ascribed, both in spiritism and mesmerism, to the agency of the evil spirits. For neither God, nor His good Angels, nor the souls in bliss could be supposed to put themselves at the disposal of spiritists or mesmerists, especially if we consider the unworthy and often immoral means employed by such men in their trades. Nor can a man claim control over the souls of the condemned; and, even if he could, it would be unholy and unwise for any one to make these his advisers and helpers. But it is perfectly conformable to the teachings both of reason and of Revelation to conclude that the evil spirits, or demons, are the agents of all such effects in spiritism and mesmerism as cannot be attributed to human power. Spiritism is explicitly forbidden in Holy Writ: " Neither let there be found any one among you that seeketh the truth from the dead. For the Lord abhorreth all such things." (Deut.. xviii. 12. See further Jouin's Evidences of Religion, pp. 74, etc.)


175. From the explanation given in the preceding article it is clear that sense-perception consists in the formation, by the sentient being, of vital images representing the material objects perceived. Now, a similar process must be followed by rational or intellectual cognition: it too consists in producing an image of the object known; not, however, an organic, a material, but an intellectual image. For truth in the mind, logical truth, supposes that the mind is made conformable to the object known; and it can acquire this conformity in no other way than by conceiving an image of that object. This point, then, is common to sensitive and to rational cognition, that both are accomplished by the formation, in the subject, of vital images representing the objects. Another point must be common, viz., both must derive the image from the object which it represents; else the cognition would not be certainly true, or conformable to the object known.

176. But a difference between sensitive and intellectual knowledge arises from the fact that, in sensitive knowledge, a material object impresses a material image of itself upon the material organ of sense; but it cannot impress a material image upon the immaterial intellect. The intellect cannot receive such an image into itself. It takes, abstracts from the material objects presented, or rather from the sensible phantasms of them, the intelligible notes of the objects; these are the immaterial images, impressed on the intellect as the species impressed; and re-acting, eliciting the vital act of cognition, the intellect forms the species expressed, thus completing the act of intellectual apprehension. The result or term of this process is an idea: here, then, we have the Scholastic theory which accounts for the origin of ideas.

177. The Schoolmen, always careful to give names to every step discernible in the analysis of any process, gave the name of intellect in action, intellectus agens, to the intellect when viewed as abstracting from the phantasms and producing the immaterial image, and the name of receptive intellect, intellectus possibilis, to the same faculty viewed as vitally receiving that image.

178. It may be asked whether all our ideas are obtained by a like process; and if so, how can we have ideas of things immaterial? Many philosophers have supposed that we have some innate ideas, ideas born in us, such as those of truth, virtue, vice, etc. Others have gone so far as to maintain that all our ideas are inborn, and only awakened, not acquired, under favorable circumstances. These are idle suppositions, devoid of all proof and, moreover, liable to the serious objection that, if our ideas are not derived from the objective reality, they may be merely subjective, and our knowledge may be an illusion. But our ideas are truly derived by way of likeness from the objects themselves; and therefore our knowledge is objective and reliable.

179. Another false theory is that of the Traditionalists, who pretend that all our knowledge comes to us by tradition, -- i.e., by the teaching of other men. This is a most unsatisfactory theory: other men can only use signs corresponding to our ideas, but not put ideas into our minds. If they give us a sign to which none of our ideas corresponds, the sign is unintelligible to us: thus, no amount of explanation can make a man born blind understand the nature of color, or the formal difference between one color and another. There remains a last false theory, that of the Ontologists, which we shall later on refute with more detail. (See Nos. 187, 188.)

180. We must first consider how we get ideas of things immaterial, inaccessible to the senses. We have no intuitions of such objects -- for instance, of virtue, vice, justice, truth, etc., nor of spirits, of God, of our own soul, etc. How do we get our ideas of all such things? The Schoolmen, in accord as usual with the ancient Peripatetics, or followers of Aristotle, clearly lay it down as a maxim that there are no ideas in our intellect which we have not derived from sense-perception, nihil est in intellectu quod prius non fuerat in sensu. This principle is true, but it needs explanation.

181. At first sight the saying appears absurd: we have an idea of spirit, but we have never beheld a spirit; how, then, can we be said to have derived this idea from sense-perception? Let us consider what we mean by a spirit: we mean an immaterial substance capable of thinking and willing. Now, by our senses we perceive material substances. By our power of abstraction we look at substance only; we strip substance of all that is material in or about it. In conceiving a spirit, we affirm substance and deny matter: our idea of an immaterial substance is partly affirmative and partly negative; but all its elements are derived by abstraction from sense-perception. But how do we get the ideas of 'thought' and 'will'? We perceive acts of thought and will in ourselves by our consciousness. But how is consciousness connected with sense? We could not be conscious of our mental acts, if these acts did not exist; and they would not exist, if sense-perception did not prompt our minds to act. For no thought, and of course no volition, would arise in the human soul, if sensation did not call forth the exercise of our faculties. Thus we see that all the elements contained in our idea of spirit are traceable to sense-perception; the same holds for all our other ideas. In fact, if we were to examine all the ideas expressed in so intellectual a poem as Milton's "Paradise Lost," we should find in it no concept the elements of which have not ultimately arisen from sensation. Many of those concepts are not conformable to an objective reality, because they are not directly formed from objects represented by them; but inasmuch as their elements are derived from real objects, all ideas have a foundation in the reality. Such are, for instance, the concepts of Death and Sin, as Milton describes those creations of his poetic mind.

182. We are now prepared to give a connected and, as it were, an historical account of the origin of our ideas according to the system of those Schoolmen who follow St. Thomas most closely. We start with the maxim, explained above, that all natural knowledge originates in sense-perception. The mind of the child is at first like a clean tablet, tabula rasa, on which nothing as yet has been written: it has no inborn ideas. Its avenues to knowledge are its senses. If these should be so clogged by disease as to be unfit for action, the intellectual powers will never be set to work; in fact, we find that persons born deaf and blind are apt to remain idiotic. When the senses of any child first open to the outward world, it begins to have sense-perceptions, as brute animals have; there is for a considerable time no sign of intellectual action. When the brain, the organ of the imagination, becomes sufficiently perfected to elaborate phantasms suitable for intellectual use, the intellect becomes aroused to its specific activity. It sets to work abstracting what is intelligible in the object, and forming an image of the object's nature. It impresses this abstract species upon the receptive intellect, which in turn seizes upon or expresses the image in itself and thus intellectually apprehends or cognizes the object. For instance, the hand seizes an orange, the eye sees it, the palate tastes it, etc.; the phantasms formed by the imagination represent all that is sensible in the fruit. The intellect goes deeper; it reads within the reality, as its Latin name signifies (intus legere, to read within); it abstracts and conceives the ideas of 'being,' 'substance,' 'accidents,' in particular of 'size,' 'taste,'' smell,' 'color,' of 'cause,'' effect,' 'food,' 'pleasures,' etc., etc. All the senses, interior and exterior, are constantly bringing new phantasms to the brain; the intellect is constantly abstracting and comparing, conceiving and judging; inductive reasoning, now fairly aroused, contributes its share to develop knowledge; and thus all our ideas are gradually formed, having a foundation in objects of sense-perception.

183. At first these ideas are not considered by us as representing whole classes of things : the ideas are direct, representing the notes 'being,' 'substance,' 'cause,' etc., which exist identically in each individual object considered; but we do not yet reflect on the fact that the objects are generically or specifically identical. For instance, when I see a rock, a fruit, a man, etc., I apprehend each as a substance; this apprehension gives me the direct universal concept 'substance.' By observation I notice the identity of the objects; but it may be a long time before I reflect sufficiently upon my direct universal concepts to perceive distinctly that they are universal -- i.e., that they represent one thing common to a whole class of things. When I do so at last, I have a reflex universal idea.

184. Philosophers have warmly discussed the nature of reflex universals. The question is a radical one; errors on this subject strike at the root of all our knowledge. The Nominalists, such as Bain and J. S. Mill, maintain that universals are mere names assigned to a whole class of things, because we choose to fix our attention on some attributes which resemble each other in different objects; they do not suppose that anything is common to such objects, but only that we give the same name to things similarly marked. They would deny that there is anything identical in all men, in all substances, etc.; simply, we classify things by an arbitrary grouping, and we assign names to the groups. The Conceptualists admit more than identity in the name; but still, they admit nothing identical in the things -- e.g., in animals, in plants, etc. They admit similarities so close that we imagine them identical, and thus we conceive, say a lion, by a sort of vague or blurred phantasm, which will sufficiently represent any lion in general. This is not an idea at all, but merely a phantasm; besides, it is essentially relative, since the word animal will not call up the same phantasm in every mind; thus conceptualism has led to the modern theory of relativity of all human thought. "It is," remarks Rev. R. F. Clarke, S.J., "the central error of modern Logic, but it has a twin brother in Metaphysics no less subversive of truth. The radical and fundamental mistake of modern metaphysicians consists in the supposition that it is possible for two objects to resemble each other without having some fundamentum in re, something truly and really common to both of them in which this resemblance has its origin." (See Amer. Cath. Quart. Review, 1888, pp. 52, etc.)

185. Thesis IX. The reflex universals are not mental images derived from universal objects physically existing, nor are they mere names, nor mere fictions of the mind; but they have a foundation in the reality of individual objects.

First part. Not images of existing universal objects, as the exaggerated Realists maintain.

Proof. Every object physically existing is a concrete and singular object, while universals are neither concrete nor singular. For instance, there is no concrete physically existing being which is a universal "body," a body that is neither large nor small nor middle-sized, neither white nor black, nor cold nor hot, etc. The universal has no definite accidents, but everything physically existing has definite accidents. Therefore there exist no physical universals.

Second part. Universals are not mere names, as the Nominalists pretend.

Proof. A mere name, or oral term, has no mental term, or concept, corresponding to it; but universal names have each a concept corresponding to them and signified by them. If they had not, all the common nouns and the verbs of a language, and most other parts of speech, would be without any certain signification; for most words express universals, and the Nominalists suppose that universals are mere names to which no definite concepts correspond. But it is subversive of all certainty to maintain that nothing definite in meaning corresponds to most of the words of men.

Third part. Universals are not mere fictions of the mind, but they have a foundation in the reality of individual things. It is here maintained that universals express some one thing which is the same in many things; while the Conceptualists maintain that there is nothing the same, but only something similar, in all the individuals of a class.

Proof 1. Similarity is impossible without something that is one in the things similar. For similarity is, as Aristotle defines it, "unity in some quality"; things are similar inasmuch as, to a certain extent, they agree or are the same. Therefore, if all things of a class are said to be similar, they are really one to a certain extent; now, the universal signifies things by that in which they are the same -- e.g., animals, plants, etc.

Proof 2. If there were not some one thing common to all the individuals of a species, then the concept could not represent the nature of that species, but only something which is not the species, but is mistaken for it; and thus all our apprehensions of universals would be founded upon mistakes; all the words of a language would have a meaning, but a false meaning. Now, this leads to universal Scepticism. Therefore universals express some one thing which is found in all the individuals of a species or genus; therefore they have a foundation in the reality of individual things.

186. The now antiquated mysticism, taught formerly by Plato, consisted in a very peculiar theory on the origin of ideas. He supposed that the souls of men, before being united with their bodies, were in another state of existence in which they saw truths intuitively; afterwards, when united with their bodies, the souls retain the truths formerly perceived, but they are unconscious of their knowledge till sense-perception comes to awaken it anew. Plato could give no proof of his conjectures; his only reason for them was that he could not in any other way account for the origin of our ideas.

187. Ontologists teach: 1. That the human soul has not in virtue of its own essence the power of knowing truth; 2. That this power must be supplied by a principle extrinsic to it; 3. That this extrinsic principle must be immediately present to the soul and directly intelligible, and must be of such a nature that in it all other things can be made intelligible to us; 4. That there can be no such being except God; 5. That our ideas, even our universal ideas, are not psychological, i.e., formed by our souls, but ontological, i.e., having objective existence, being the objects known to us. Still, many Ontologists allow that our mind can, by means of reflection, form to itself psychological ideas, which it can then compare with the ontological, thus knowing them to be conformable to the objective truth.

188. Thesis X. Ontologism does not properly account .for the origin of our ideas.

Proof. That theory does not properly account for the origin of our ideas, 1. Which does not give a good explanation of known facts; 2. Which makes gratuitous and even false suppositions; 3. Which leads to false conclusions. But such is Ontologism.

1. It fails to give a good explanation of known facts. (a) It is a certain fact that our knowledge is intimately dependent on sense-perception; why is this so, if we see truth in God? (b) We know all things in connection with phantasms: bodily things by their own images, and things immaterial by reference to images borrowed from matter; why is this? The very terms applied to immaterial things are taken from material objects, e.g., incomprehensible, immaterial; an acute, sharp, dull, clear intellect, etc. (c) We have no consciousness, even on reflection, that we see God; why is this, if we see Him?

2. It makes gratuitous and even false suppositions: (a) That actual finite beings are not cognoscible in themselves; why are they not cognoscible in themselves, if they have their own entity? (b) That we see things in God, and still we do not see God; why is this? (c) That we know God by species taken directly from Him, and other things by species taken from God; the opposite is evidently the case.

3. It leads to false conclusions; for, as entity and intelligibility are convertible terms, if finite things have not their own intelligibility, it will follow that they have not their own entity distinct from God's entity, that they are one with God; thus Pantheism is arrived at as a logical conclusion from Ontologism. In striving to refute this argument, Ontologists contradict and refute each other, and are divided into a number of schools: Malebranche claims that all things become intelligible to us by means of their archetypes, which we see in the Divine essence; Gioberti maintains that we do not behold the essence of God, but His creative act, Ens creans existentias; Rothenflue supposes that we see God "merely as being," esse simpliciter, etc. Therefore Ontologism does not explain the matter properly.

189. In connection with the study of ideas we must speak briefly of the expression of our ideas by words or articulate language. A word is an arbitrary articulate sign of an idea; therefore the same word has not the same meaning in different languages. Hence words cannot of their own force communicate our ideas to other men; but they are readily associated with ideas so as to become their inseparable companions. It would be incorrect to say that we cannot think without words: in fact, we often form ideas, judgments, trains of reasoning, and we experience feelings which we have no words to express, and deaf-mutes have no articulate signs at all. Still, thought without articulate language would be far less distinct, more embarrassed in its process; and the minds of children would develop much more slowly and imperfectly if it were not for the use of speech.

190. As to the origin of language, it need not be to us a subject of vague speculation. We know from the historical account of Genesis that man had a language from the beginning, which he to a certain extent elaborated under the direction of the Creator (Gen. xix. 20); but he was then, before his fall, in a state of higher mental and bodily perfection than he is now. The question has often been discussed whether, with none but his present mental powers, man could have invented a language. No one doubts that it would have been difficult to do; it iseven difficult now to make any decided improvement upon any nation's tongue. Still, there appears to be no conclusive reason to deny that it might, perhaps, have been gradually effected. To give a history of the supposed development of language, as Evolutionists sometimes attempt to do, is an idle task, always most unsatisfactory and never scientific.

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