CHAPTER III.

THE BRAIN A PART OF THE MIND.

CLXVII.

1. We have irresistible evidence for the induction, that the unconscious part of the mind is corporal, and that the brain is either a part or the whole of it: the evidence makes it highly probable that the corporal part of the mind consists of the encephalon, spinal marrow, afferent and efferent nerves, and the peripheral parts of the organs of sense. As regards the latter we have the sanction of a datum for the belief that they are subjects of the sensations and sense-perceptions proper to them. It is true that when experience develops belief in a spiritual subject of consciousness this datum is discredited, (it has been proved to be inconsistent) and then the organs of sense are accounted mere accessories or instruments of the mind, bearing to it such a relation as a telescope bears to the visual faculty; but when the mental effects of concussion of the brain and cerebral lesions and disorders otherwise caused expose the relation of cause and effect that exists between cerebral event and consciousness, such that the brain can no longer be considered a mere accessory but must be allowed to be a part of the mind, the

credit of the datum respecting the organs of sense is so far restored that it is no longer easy to refuse to rank those organs as parts of the mind.

2. That all knowledge and skill depend upon modifications of the brain caused by experience and mental exercises of every kind, is proved by the fact that a concussion of the brain may deprive one of all knowledge and skill without impairing the power of the mind to recover both; the former from new experience, the latter from new interaction of the Ego and its environment. Certain cerebral lesions deprive the mind not of all knowledge, but of a considerable part, and others of a minute part so oddly selected that, as some one has remarked, it would seem as though Puck had been sporting with the brain. These facts shut us in to the conclusion that the extinction of knowledge or skill, or of both, is due to an effacement or impairment of durable cerebral modifications. They are conclusive that conscious knowledge and skill active are effects of an action of those modifications, that a series of unintuitable corporal events underlies, as cause and condition sine qua non, all such consciousness and activity of skill as cerebral lesion has the property of destroying or suspending. Concussion of the brain has been sometimes followed by a remarkable enhancement of mental faculty. General paralysis often begins its terrible work by an enhancement of mental faculty; idiotcy and bodily impotence are always the accompaniments of its regular final stage. The psychical effects of other diseases, like those of concussion, attest the dependence of mental faculty on corporal constitution, and of consciousness on corporal event. A servant girl whom disease had reduced to idiotcy was temporarily restored

to mental integrity by a fever such as ordinarily causes delirium.1 A beginning of insanity has raised the mind of a person bordering on idiotcy to the ordinary level of ordinary intelligence. An abscess formed under the scalp has converted a violent headache into spectral illusion.3 Impending apoplexy is sometimes wonderfully prophetic, predicting truly the time of the death of the subject. It is sometimes a source not only of prescience but also of melodramatic invention explanatory of the expected event. A patient who suffered from an excess of blood in the brain, expecting an imminent effacement of consciousness, used to undergo a melodramatic hallucination put as explaining the event. A witch seemed to rush upon him and strike him on the head with a stick. The effects of hanging and drowning sometimes corroborate the testimony of concussion and disease as regards the dependence of consciousness on cerebral event. A gentleman who in great depression of mind attempted to hang himself but was cut down in time to save his life, related that the strangulation plunged him into ecstasy in which he re-lived his childhood and boyhood." Drowning has sometimes occasioned a panoramic display of the past. The mental effects of narcotics, anæsthetics, and stimulants, such as opium, hashisch, chloroform, and alcohol, add their testimony to the dependence of consciousness on corporal event. We have striking instances of the dependence of the moral faculty on bodily states. Certain disorders, e.g. uterine changes, transform honest people into thieves.

6

1 Physiology and Pathology of the Mind. Maudsley, p. 260.

2 Obscure Diseases of the Brain. Winslow, p. 273.

3 Ibid. p. 457.

♦ Ibid. p. 312.

5 Ibid. p. 440.

• Ibid. p. 442.

Com

mon and familiar facts prove the causative and moulding bearing of bodily states upon consciousness. Sleep bears in this way on the consciousness, dreaming. Coma is a bodily state that excludes consciousness. The feeling of well-being, and the pride of life incident to health and a favourable atmosphere, are consciousnesses that result from bodily states. The differences of consciousnesses characteristic of youth and of age are effects of bodily states.

CLXVIII.

It follows from the foregoing evidence that, as regards man, every consciousness except volition is an effect of an unconscious corporal event, and that every consciousness including volition depends upon an unconscious corporal event. Had psychological research begun with, or early achieved this knowledge, it would have been spared much error. It would have been exempted from the error, that discernment of primary Kinds supposes discernment of their differentia. It was obvious that generalisation depends upon likeness and difference and that likeness supposes a somewhat in respect of which the like things are like. Psychologists therefore seemed to be shut in to the conclusion that knowledge of a differentia is a sine qua non of knowledge of a kind. It did not occur to them that the differentia might, by a latent bearing on the mind, cause, or contribute to cause, knowledge of the kind— that it might have the property of causing an unconscious corporal event of which knowledge of a kind

might be an immediate effect; in which case knowledge of a kind might obtain without knowledge of its differentia. Here we have an instance of mere privation of hypothesis conferring upon a thesis an air of necessary truth. So much did the thesis, Discernment of a kind supposes discernment of its differentia, seem to be a necessary truth, that the error persisted in spite of the incompatible fact that the differentice of many primary kinds eluded scrutiny, e.g. that of mankind. Had the dependence of consciousness on corporal event been known the incompatibility would have suggested the explanation that the corporal event which causes discernment of a primary kind does not cause discernment of its differentia. This knowledge, it is probable, would also have prevented the error that analysis of consciousness is incapable of discovery, - incapable of augmenting knowledge-that to be known is essential to the constituents of consciousness. The greater part of the wealth with which psychology enriches man is, with slow toil, quarried out of the records of consciousness.

The knowledge would have deprived of plausibility the reason of the scepticism of Hume, viz. that power is not perceptible, and it would probably have prevented Kant's doctrine of knowledge à priori; for, when it is allowed that the consciousness constituting an experience is an effect of a corporal event, consistency makes no objection to the competence of the cause to impart to the object, in certain cases, a symbol of power or one of absoluteness, and parsimony demands that all knowledge which can be consistently accounted the offspring, either immediate or remote, of experience, shall be so accounted. Privation of the knowledge put us under