The intellectual feeling also has its pathology, in connection with which I have to point out two principal cases: the extreme forms of doubt, and the introduction of mysticism into science.
1. Doubt is a state of unstable equilibrium in which successive contradictory representations neither mutually exclude nor conciliate each other. I distinguish simple doubt, dramatic doubt, and the insanity of doubt.
In simple or limited doubt, intellectual indecision has as its emotional accompaniment a slight uneasiness, a state of discomfort resulting from an unsatisfied desire, a tendency which comes to nothing. Under this form doubt is normal, legitimate, and even necessary; it becomes morbid when it takes a chronic, permanent, and aggressive form, when it produces a violent shock and a long reaction.
This is the doubt which I call dramatic, because it is an internal convulsion, a crisis which often lasts a long time and repeats itself. It precedes great conversions and then subsides, but sometimes lasts through life, as with Pascal. There is nothing surprising in its violence, since it is, in the intellectual order, the equivalent of an intense, incurable, and hopeless love; in the two cases the situation and effects are identical.
The insanity of doubt takes us further into the intricacies of pathology. It is “a chronic disease of the mind, characterised by constant uneasiness.” It presents numerous varieties, which have been classified by alienists. Some do not pass beyond the region of every-day trivialities, as the man who will return twenty times to see whether he has really locked his door. Others exhaust themselves in abstruse and insoluble questions, never able to satisfy themselves or stop, like an ever-turning wheel. Others, the timid, lose themselves in endless scruples and puerilities. But, whatever be the matter to which the mind applies itself, the psychological process remains the same. It is a questioning without pause or limit, accompanied by distress, constriction of the head, epigastric oppression, vaso-motor troubles, etc. There is the ardent desire to find a fixed state for thought without the ability to do so.
Under its gravest form it is “the complete loss of all notion and feeling of reality.” It is absolute scepticism, not theoretic and speculative, after the manner of the Pyrrhonians, but practical, bearing not only on ideas, abstract conceptions, memories, reasonings, but even on perceptions and actions; the exercise of the intellect is not accompanied by any belief—i.e., any state of mind which presupposes a reality. “I exist,” says one of these patients, “but outside real life and in despite of myself ...; something which does not seem to be in my body impels me to act as I formerly did, but I cannot succeed in believing that my actions are real. I do everything mechanically and unconsciously. My individuality has completely disappeared; the way in which I see things makes me incapable of realising them, of feeling that they exist.... Even when I see and touch, the world appears to me like a phantom, a gigantic hallucination.... I eat, but it is a shadow of food entering the shadow of a stomach; my pulse is only the shadow of a pulse.... I am perfectly conscious of the absurdity of these ideas, but cannot overcome them.”[[238]] This state belongs, in fact, to the category of conscious madness.
But it is not essentially a disease of the understanding: the intellectual element is secondary; this perpetual doubt, these endless questionings are merely the effects; the cause lies in a weakening of the emotional life and the will, rendering them incapable of arriving at a belief—i.e., an affirmation—and, more deeply still, in a disturbance of the organic life, as demonstrated by sensory perversions, motor enfeeblement, and the melancholic state of the patient with its physiological accompaniments, and lowering of the vital functions.
2. The introduction of mysticism into science, though particularly prevalent just now, is an intellectual disease incident to all ages. In the beginning, scientific research had no clear consciousness either of its method or its object.
The earliest Greek philosophers speculated at once on first causes, second causes, and practical applications, without drawing any hard and fast distinction between these subjects. Thales constructed a cosmology and calculated eclipses; Pythagoras reduced the universe to numbers, but he also greatly advanced the study of mathematics, and founded a communistic society on his own principles. By slow degrees the proper domain of science became recognised: the determination of second causes, of natural laws. At the Renaissance, alchemy, astrology, and the occult sciences were discredited, in spite of their provisional services, and some positive discoveries due to them. At present, the methods are fixed, in their main lines; a fact which permits us to determine the anomalies and deviations of the intellectual sentiment.
How does it deviate from the normal track? It is needless to remark that it is not by seeking the unknown, since this is its fundamental task, for every day and for all time. Is it by pursuing the unknowable? This view is scarcely tenable, for how can we determine where the unknowable begins? Let us admit, for the sake of argument, and in order to simplify matters, that this word covers the whole region of first causes, taken as inaccessible; but, having eliminated these, only by an arbitrary act can it be decided that this or that thing is unknowable. The history of science supplies us with proofs in abundance. To give but one example, which is closely connected with psychology: one of the greatest physiologists of the century, J. Müller, declared that the time necessary for perceiving a sensation is not measurable and can never be determined; this, however, did not prevent Helmholtz from measuring it some years later, and it is well known what successful experiments have since been made in that direction.