Popular Science Monthly/Volume 35/October 1889/Origin of Some General Errors


By Herr S. EXNER.

WHILE we endeavor to distinguish between instinct and reason, we are accustomed to speak of such skill and conformity of actions to a given end as are exhibited by birds in building their nests, or by societies of insects, as more resembling what we call reason. We may mark the difference, however, by observing that instinct develops its qualities only within a limited sphere and in view of a limited end. Birds can weave filaments into nests, attach them to branches, and adapt the forms of their work to those of the tree and its limbs; but their talents in weaving are of no use in helping them release themselves when caught in a snare, and they will then struggle as wildly and vainly as an animal that never built a nest. A hen will lay an egg every day in the same place till the quota is completed, and will then sit upon them; but many hens will sit all the same, and for the full time, if the eggs are taken away as they are laid. These examples illustrate how instinctive processes are produced simply as determined combinations—or work only in view of a special end. The actions provoked by them will remain the same, even when they have become purposeless. On the other hand, the associations of the processes can not be broken, and the skill which the bird directs to building her nest is not capable of being employed for any other end.

The more developed the instinct, the more stable are the combinations of phenomena and nervous conditions under which it works; the weaker the combinations, the more nearly the animal's mode of action approaches what we call reason. We should judge of the intelligence of an animal, not by single acts surprising to human understanding, but according to the diversity of the situations in which that animal can use its faculties. The weakness of reason in the animal always has the same character, and lies in the impossibility or difficulty of breaking certain associations and the incapacity to produce out of two combinations, by transferring a number from one to the other, a third. Hunting-dogs show great skill in threading mountain-paths and overcoming or avoiding obstructions, but no dog will remove a branch interposed in his way. When the associations by which instinct works come into play outside of or against their ordinary end, we may speak of their working as imperfect, and may say that the animal is mistaken.

We also have instincts that are characterized by the narrowness of their end. Among them are the reflex actions. The eyes wink when they are threatened with injury; but they also wink when a beneficial operation is performed upon them, to which the winking is an obstacle, the action going on all the same when it is useless or injurious.

I believe it can be shown that this type of instinctive action is also found in man, and that the origin of many types of errors may be found in the application to particular cases, but exceptional, of what is generally right. This proposition is confirmed by some errors of the senses. When a point on our retina is excited by an external pressure, we fancy we see something luminous in the ordinary field of vision of that point. Were it not for the experience of previous observations of objects and their reflections, we should localize as things behind the glass the reflections which we see in mirrors. In this and most like cases, we are acquainted with the mechanism of the phenomenon, and can distinguish between what is only the sensorial impression and what we owe to memory. The separation vanishes in the higher regions of psychic life. If we draw a line on a sheet of paper and cover the end of it with another sheet, an observer not in the secret will imagine it to be much longer than it is, because his conception is based upon the fact that when one object lies upon another, it usually covers a considerable portion of it. We are subject to a considerable number of illusions of this kind. The prestidigitator takes advantage of one form of them when, by a quick look to one side, he turns the eyes of the audience away from his manipulation and gains an opportunity to execute the trick without detection, although every one of his spectators had determined not to lose sight of his hands. He is aware that a glance and particular adjustments of the head and eyebrows and lids will usually suggest to the looker-on that he will see at a particular point something more interesting than anywhere else within his field of vision. At the same time the audience will not know why they looked in that direction, and may not even be conscious of having looked there.

We thus deal on this domain, remote from the physiology of the senses, with functions of the nervous system similar to what we have seen in the hen and the winking. Thought follows its course according to the usual process; with more or less of consciousness the ordinary train of associations is formed, and the judgment corresponds with what is correct in most cases. There is, therefore, no precise limit between instinctive actions and conscious thought; for every one can observe in his own mind that thought rests considerably on phenomena of association. An elevated intelligence is, however, distinguished from an inferior one by its richness in associations. The faculty of transposing the elements of one complexus of observations into another, the possibility of making a new combination, and the wealth of associations, are prime factors in determining the degree of intelligence. A large proportion of the mistakes to which we are liable originate in this kind of instinctive succession of associations usually correct and effective, in which associations important to the particular case are wanting. In other words, they arise from the association of the habitual with the omission of the special.

The thought can be illustrated by the citation of a few widespread logical errors. Where lotteries are drawn, the lists of the drawings are earnestly scrutinized by unsuccessful investors, who, if asked why they do so, will reply that, as all the numbers must eventually be drawn an equal number of times, those which have not been drawn for a long time stand the best chance of coming out soon. People often say, when it is raining hard, that it will be made up for by fine weather afterward. A kind of belief exists in a compensating providence that will bring grief after a long run of happiness; and it is illustrated in the legend of the ring of Polycrates. The mental processes leading up to error in these instances start from the premise that all the numbers have the same chance of winning; with which is associated the anthropomorphic idea of distributive justice, taking, in the legend of Polycrates, the form of divine jealousy; our recollections witnessing to a tendency to change; and past experience, teaching that, among a given number of objects, the probability of a particular one being found soon increases in proportion as the others are sorted out and put away; or, as in the filing past of a regiment, our expectation of finding our friend in the next rank grows as companies pass in which he does not appear. All this is true in general. The factor the omission of which in the particular case leads to error is that in the lottery all the numbers are put back into the urn before each drawing, and consequently what has been done has no influence on the probabilities of the present case.

So, when a certain person is spoken of as having "luck" at play; while he may have had unusual success—that is, a high number of favorable chances among all the possible ones—for a day or several days in succession, any association of his "luck" with his personal qualities is mistaken. We usually reason correctly that men succeed in their lives and enterprises whose personal qualities contribute to their success; but in this case there is no possible connection between the disposition of the cards and the qualities of the player. These associations are generally based upon supposed experiences, in which, besides the impossibility of securing exact observations, we commit the mistake of confounding coincidences with causal relations. We need not be surprised at them. They are incident to the relations of men with one another, and are confirmed by false observations and tradition, and they are what give its special character to each epoch.

These typical errors are not only met in the domain of common life; preserving their character, they possess the highest spheres of our activity, art and science; and in those domains we can see the fundamental difference between these two modes of the mind's action. While in science, the object of which is the truth, every error involves mischievous consequences, in art, which looks to the beautiful, illusion has full play, and in many instances even forms the basis of the best conceptions. Thus, in architecture, a balcony supported on slender bars of iron does not offer a pleasant appearance to us, while we are ready to admire the same structure if it rests upon shapely brackets of stone projecting to an equal distance from the wall. The apparent disproportion between the structure and the support in the former case is an artistic fault. It does not lie, however, in the calculations of the architect, which may be perfect, but in the "instinctive" judgment of the speaker. The prejudice is so general that architects often dress slender supports of iron with false brackets of plaster that will convey a more agreeable impression.

The psychological origin of this prejudice is found in our familiarity, from experience, and from having seen it used in buildings, with the solidity of stone, while we are not so well acquainted with the equivalent strength of less massive iron. In most cases the impression of solidity agrees with the sense of beauty, while the apparent disproportion of iron supports grates upon it. The balcony continues to look unwieldy even after we have become assured that the iron bars are amply strong. Our sense of beauty, therefore, rests upon an illusion in the presence of which it can not adapt itself to the particular case; but it is an illusion that every artist ought to regard. Such illusions are common in all art.

The proposition, "Style is the concordance of an artistic work with the history of its development, with all the circumstances of its production," which is elucidated in Gottfried Semper's work on "Style," defines the psychologic basis of every artistic production. For a work can have style only as it is in harmony with the mass of associations, mostly unconscious, which the spectator forms on the subject of its composition. This is why a majolica cup should have a different shape from one of metal; why a cup of hammered metal should be distinct from a molded one; and why vessels of other materials should have their specific forms.

I have intimated that many of our most common associations arise from impressions that have acted upon us from our youth. The nature of these impressions is conditioned on the experiences of the generations that have preceded us. In other words, these traditions play an important part in our aesthetic impressions. The Greeks employed in their marble temples motives that dated from a distant epoch when building was done with wood. A diversion from these rules would have produced an unpleasant impression on the Greeks, and would have been contrary to the "style." Our case is not different. All of our ornamental motives are derived from time-honored traditions; and our æsthetic satisfaction in them continues unharmed by the reflection that in many cases they are no longer adapted to present conditions.

We meet errors of a similar class on scientific ground. Take, for example, the paradox of Zeno the Eleatic, concerning Achilles and the tortoise. The swift Achilles, it supposes, can never overtake the tortoise, because a distance intervenes between them, and he will have to run for a certain time before the distance is reduced by half, another length of time to reduce it to a quarter, to an eighth, and so on to infinity. More time is required to reduce the rest of the distance by half, and the number of these possible parcels is infinite; hence Achilles will never catch up with the tortoise. Now, since we know that he will overtake it, wherein is the sophism? It is not in any real contradiction between the laws of our thought and experience; but a typical error is involved, in which thought, moving in a way that generally leads to the truth, is at fault in the special case. It is true, in ordinary cases, that when we continue adding indefinitely new intervals to any interval of time, the sum of all will be infinite. This fact, generally valid, in the particular case leads our judgment to a false conclusion. The special feature in the problem is that if parcels of time, infinite in number, diminish according to certain laws, their sum will not be infinite, but may be very small. We do not have to be accomplished in mathematics to comprehend the sophism and find its solution. Every one knows that we can divide a length of one metre into a half metre plus a quarter, plus an eighth, etc., of a metre, and thus obtain an infinite number of factors, the sum of which, however, shall always be within a metre. The general error involved in the discussions of this sophism is also a typical one, for it originates in the predominance in our consciousness of the general law, with the non-association of the particular case. The phenomenon is therefore analogous to those which we have observed in animals, to errors of the senses, and to other illusions of the reasoning faculty.

From the hen that sits on its empty nest to the problem of Zeno the Eleatic, there runs through animals and men a continuous series of errors, all of which have a common origin in the working of the nervous system conformably to the majority of cases without regarding any certain special and exceptional case. The typical character of these errors is related to the phylogenic development, and casts a degree of light on the unfolding of thought.—Translated for the Popular Science Monthly from the Revue Scientifique.

  1. From a communication to the Sixty-first Congress of German Naturalists and Physicians.