highly irrascible, liberal in permitting the use of the horse for days at a time and again tyrannical in the insistence upon foolish conditions, clever in his method of instruction and yet at the same time possessing not even the slightest notion of the most elementary conditions of scientific procedure,—all this, and more, goes to make up the man. He is fanatic in his conviction, he has an eccentric mind which is crammed full of theories from the phrenology of Gall to the belief that the horse is capable of inner speech and thereby enunciates inwardly the number as it proceeds with the tapping. From theories such as these, and on the basis of all sorts of imagined emotional tendencies in the horse, he also managed to formulate an explanation for the failure of the tests in which none of the persons present knew the answer to the problem given the horse, and also for the failure of those tests in which the large blinders were applied. And he would often interfere with or hinder other tests which, according to his point of view, were likely to lead us astray. And yet, when the first tests with the blinders did turn out as unmistakably sheer failures, there was such genuine surprise, such tragi-comic rage directed against the horse, that we finally believed that his views in the matter would be changed beyond a doubt. "The gentlemen must admit," he said at the time, "that after seeing the objective success of my efforts at instruction, I was warranted in my belief in the horse's power of independent thought." Nevertheless, upon the following day he was as ardent an exponent of the belief in the horse's intelligence as he ever had been.

And finally, after I could no longer keep from him the results of our investigation, I received a letter from him in which he forbade further experimentation with the horse. The purpose of our inquiries, he said, had been to corroborate his theories. On account of his withdrawal of the horse a few experimental series unfortunately could not be completed, but happily the major portion of our task had been accomplished.

THE HORSE OF MR. VON OSTEN

CHAPTER I

THE PROBLEM OF ANIMAL CONSCIOUSNESS AND "CLEVER HANS"

If we would appreciate the interest that has been aroused everywhere by the wonderful horse solving arithmetical problems, we must first consider briefly the present state of the problem of animal consciousness.[C] Animal consciousness cannot be directly gotten at, and the psychologist must therefore seek to appreciate it on the basis of the animal's behavior and with the assistance of conceptions borrowed from human psychology. Hence it is that animal psychology rests upon uncertain foundations with the result that the fundamental principles have been repeatedly questioned and agreement has not yet been attained. The most important of these questions is, "Does the animal possess consciousness, and is it like the human consciousness?" Comparative psychologists divide into three groups on this question.

The one group allows consciousness to the lower forms, but emphasizes the assertion that between the animal and the human consciousness there is an impassable gap. The animal may have sensations and memory-images of sensations which may become associated in manifold combinations. Both sensations and memory images are believed to be accompanied by conditions of pleasure and of pain (so-called sensuous feelings), and these in turn, become the mainsprings of desire. The possession of memory gives the power of learning through experience. But with this, the inventory of the content of animal consciousness is exhausted. The ability to form concepts[D] and with their aid to make judgments and draw conclusions is denied the lower forms. All the higher intellectual, æsthetic and moral feelings, as well as volition guided by motives, are also denied. Among the ancients this view was held by Aristotle and the Stoics; and following them it was taught by the Christian Church. It pervaded all mediæval philosophy, which grew out of the teachings of Aristotle and the Church. It is this philosophy, in the form of Neo-Thomism, which still obtains in the Catholic world.

During the 17th century, even though temporarily, another conception of the consciousness of lower forms came to prevail and was introduced by Descartes, the "Father" of modern philosophy. Far more radical than the earlier conception, it denied to animals not only the power of abstract thought, but every form of psychic life whatever, and reduced the lower form to a machine, which automatically reacted upon external stimuli. This daring view, however, prevailed for only a comparatively short period; but owing to the opposition which it aroused, it gave a tremendous impetus to the study of animal consciousness. Most of the great philosophers following Descartes, such as Locke, Leibniz, Kant, and Schopenhauer, however greatly they may have differed in other points, in this one returned to the Aristotelian point of view.

A third belief avers that animal and human consciousness do not differ in essentials, but only in degree. This conclusion is regularly arrived at by those who regard so-called abstract thought itself, as simply a play of individual sensations and sensation-images, as did the French and British associationists (Condillac and the Mills). The superiority of man accordingly consisted in his ability to form more intricate ideational complexes. Again, this conception of the essential similarity of the human and the animal psyche has also always been arrived at by the materialists (from Epicurus to C. Vogt and Büchner) who impute reason to the animal form as well as to man. The same position is, furthermore, taken by the evolutionists, including those who do not subscribe to the doctrines of materialism. It has almost become dogma with them that there exists an unbroken chain of psychic life from the lowest protozoa to man. Haeckel, preëminently, though not always convincingly, sought to establish such a graded series and thus to bridge the chasm between the human and the animal consciousness.

Two tendencies, therefore, are discernible in animal psychology. The one seeks to remove the animal psyche farther away from the human, the other tries to bring the two closer together. It is undoubtedly true that many acts of the lower forms reveal nothing of the nature of conceptual thinking. But that others might thus be interpreted cannot be denied. But need they be thus interpreted?—There lies the dispute. A single incontrovertible fact which would fulfil this demand, [i.e., proof of conceptual thinking], would, at a stroke, decide the question in favor of those who ascribe the power of thought to the lower forms.

At last the thing so long sought for, was apparently found: A horse that could solve arithmetical problems—an animal which, thanks to long training, mastered not merely rudiments, but seemingly arrived at a power of abstract thought and which surpassed, by far, the highest expectations of the greatest enthusiast.

And now what was it that this wonderful horse could do? The reader may accompany us to an exhibition which was given daily before a select company at about the noon hour in a paved courtyard surrounded by