In contrast with this view, I shall here introduce an extract from Hæckel's Evolution of Man, as he may be accounted the most advanced advocate of the theory of "mind-cells." He says,—"The nerve cell of the brain is an extremely one-sided formation. It can not, like the egg-cell, develop from itself numerous generations of cells, of which some transform themselves into skin-cells, some into flesh-cells, and others into bone-cells, etc. But instead, the nerve-cell, which is formed for the highest activities of life, possesses the capacity to feel, to will, to think. It is a true mind-cell, an elementary organ of mental activity. Correspondingly, it has an extremely complex minute structure. Innumerable filaments of exceeding fineness, which may be compared to the numerous electric wires of a great central telegraph station, traverse (crossing each other again and again), the finely granulated protoplasm of the nerve-cell, and pass into branched processes, which proceed from this mind-cell, and connect with other nerve-cells and nerve-fibres. It is scarcely possible to trace, even approximately, the tangled paths of these filaments in the fine substance of the protoplasmic body. We thus, have before us a highly complex apparatus, the more minute structure of which we have hardly begun to know, even with the help of our strongest microscope, and the significance of which we rather guess than know. Its complex mechanism is capable of the most intricate physical functions. But even this elementary organ of mental activity, of which there are thousands in our brain, is only a single cell. Our whole intellectual life is but the sum of the results of all such nerve-cells, or mind-cells."[DF]
From this passage it will be seen that ascertained facts are given in harmony with previous descriptions; but that while naming some as sensory, others as motor, there is no distinct evidence for classifying certain cells as "mind-cells." Along with the admission of our comparative ignorance of the minute structure of the cell, is the assertion that this cell "possesses the capacity to feel, to will, to think." This latter statement is advanced without any trace of scientific evidence, and has no better substratum on which to rest than the admission that man not only feels, but also thinks and wills. Further, when we recall the singular variety of situation in which these cells are found, as they lie within the spinal canal, subordinate centres, and the brain, the insufficiency of the whole theory of "mind-cells" is apparent. Still more conspicuous does this become when we turn to Hæckel's illustrative diagram, and read underneath it this description,—"A large branched nerve-cell, or 'mind-cell' from the brain of an electric fish." The investigator who makes in the directest manner statements as to thinking and willing, which he has not verified and can not verify; and who with undisturbed composure of mind proceeds to illustrate and support his position by giving a drawing of the "mind-cell of an electric fish," does almost every thing that can be done to discredit his testimony on scientific subjects.
Having now set forth the grounds on which I think it clearly shown that physiological science has done no more than identify sensory and motor cells; and that the search for the true "mind-cell" has proved a failure; I pass from this division of the subject with the acknowledgment that the front and back portions of the brain still present area for fresh research, and to this must be added the striking fact that in all the brains subjected to electric excitation these two portions have uniformly remained silent. These considerations may possibly hereafter afford valuable suggestions towards guidance of the work yet to be done in the investigation of brain structure and functions.
In view of the limits of the present discussion, I shall at this point pass over at once and directly to the region concerned with the government of human conduct, with the view of illustrating in what respects human life differs from merely animal life. On this single test, I must here be content to rest an argument for the insufficiency of physiology, and the necessity for observation of our own experience, if we are to have an intelligible account of the most familiar characteristics of human life. By way of securing a sharp contrast serviceable for illustrative and argumentative purposes, I take an extract from Mr. Darwin. His statement is this,—"There is no evidence that any animal performs an action for the exclusive good of another."[DG] Alongside of this statement, for the purpose of comparison and contrast, let me place this. It is an essential law of human life, having daily application, that man shall so act as to make the good of his fellowman the express end of his action. This is a law of moral life which we do not dream of applying to any lower order of beings, but which we do regard as binding on all men equally. Explicit testimony to this law of human life may be drawn from the philosophy of Greece and of China in times so remote as to precede the Christian era, or from the teaching of our Saviour, or from the daily life of men in any land in this nineteenth century. The contrast is thus sharp enough, and it presents the most perplexing difficulty for physiologists of the school of Hæckel; while it affords the strongest line of evidence for that philosophy which accounts for the higher characteristics of human life by reference to mind as distinct from brain, and immeasurably higher in function.
Whether Mr. Darwin's account of animal conduct will be uniformly accepted by naturalists, need not concern us, as the possibility of dissension would not seriously affect the argument, the main stress of which must fall on these two points, that the law of pure benevolence is a law of human life, and that the mere recognition of this law (I do not say obedience to it, which is a stage further in advance), can not be included within the functions of brain.[DH]
From what has been written by some naturalists as to the "benevolence" of animals, it is probable that some may be prepared to take exception to the statement of Mr. Darwin. There is no need for here entering upon discussion which might thus be raised, and which would entail the task of criticising multitudes of statements made in a singularly loose and unscientific manner. There is not any more careful observer than Mr. Darwin, the whole record of whose observations gives confidence in his testimony, and his patient reflection on the real significance of what he has seen. We may, however, leave this matter to naturalists, that they may decide whether this conclusion as to animals requires some modification. The purpose of the present argument is to show that an authoritative law of benevolence does apply to human life, in direct contrast with the ordinary law of animal life, giving special force to the struggle for existence as witnessed in the history of the lower orders of beings.
One possible entanglement for the present argument must, however, be carefully shunned. In the comparison between man and animal, we are apt to diverge into a discussion of what men and animals severally do. This is a question considerably different from that now under discussion, and yet it lies in such close proximity as to afford the greatest facilities for confusion of thought. We are not here comparing what animals do, with what men do; we are comparing the actions of animals with what we know men ought to do. It is this question of ought which appears as the outstanding and distinguishing feature in human life, on which we are now seeking to direct attention with all the concentration which physiologists secure when the microscope is directed on brain tissue. The true feature here is elevation and complexity of intellectual action, and the possibility of assigning this to brain action. The question is no doubt concerned with conduct both in the animal, and in man,—but what we wish to ascertain is, how far action or conduct in the two cases throws light on the exercise of intelligence possible to man and to animal. It is admitted that to act on a law of benevolence requires a higher exercise of intelligence, than to act under a law of desire or sensitive impulse; and we wish to reach definite conclusions on two points; first, and subordinately, whether animals ever act on the higher law; second, and chiefly, whether such action does not involve as its condition an intellectual exercise of a higher order than can be assigned to brain. The former of these questions, subordinate to the present inquiry, may be left to naturalists. The second concerns us directly here, in the more important discussion as to man.
With the view of completing the defence against disturbing entanglement, it may be well further to insert here the explicit statement that men do very commonly act in neglect of the law of benevolence, and even in violation of it. The fact is too well known in society to be overlooked. It may be enough, however, in the present connection, to admit that men do often act like the animals; or, to state the fact more precisely in form, the animal nature is often found governing men, so as to make their action resemble that of the lower animals in the struggle for existence.
These lines of severance will now make clear what is our main question,—Is man capable of recognizing a higher law of life? Does a law of benevolence apply to him as a rational creature, as it can not apply in the history of the animals around us? And if this question be answered in the affirmative, does such answer imply the exercise of a higher power than can be scientifically assigned to brain cells?
That man recognizes a law of benevolence as determining personal conduct will not be formally disputed by any one. Yet so very much bearing on the present argument is involved in the interpretation to be assigned to this admission, that it is desirable to present at least in outline, the evidence on which the statement rests. If we look at the facts in view of the ordinary actions of the lower animals, a series of contrasts is presented. The animals are seen to compete with each other for what is a common object of desire, such as a favorite article of food; and to fight with each other for possession; the consequence is that the strongest and most daring get what they seek, while the weaker and more timid must be content with what is of less value for gratification of their desire. These facts are so conspicuous and so constant in their influence on the whole race of animals that the theory of the origin of species by descent founds upon them. A complete contrast appears in what man recognizes as the rule of his conduct, when he admits the obligation to benevolence. There is a reflective exercise concerned with the right and wrong in human conduct which regards it as a wrong thing for a man to snatch from another the enjoyment within his reach, or subvert his opportunity for happiness in order to increase his own pleasure. On the other hand, there is an exercise of thought which contemplates effort for the good of others as right, even extending the application of this law of moral life so far as to require self-denial, and, in circumstances of special importance, self-sacrifice, for the good of others. These are facts so elementary, that the statement of them would be felt to be uncalled for, were we not seeking to distinguish the elements of our ordinary experience. In accordance with what has been said, we are agreed in regarding it as a wrong done to another if we deprive him of enjoyment simply for the sake of our own satisfaction. Such conduct is what we condemn as selfishness in the agent, and a wrong to the sufferer. When on the contrary we subordinate personal pleasure in order to secure the happiness of another, we commend the benevolent disposition in which the act originates, and we honor attention shown to the rights of a fellowman. As the contrary lines of conduct are so often followed, and even vindicated as permissible in the competitions of life, we need to show with some care that the law of benevolence is uniformly regarded as a law of human conduct even when its requirements are unfulfilled. This becomes obvious if we look along another line of observation. If we pass from what a man does to his fellowmen to what he is seen to expect of them, we at once perceive that the authoritative feature alleged to belong to the principle of benevolence is admitted by him. He resents the selfishness from which he has suffered, complains of the unmanly act which found its pleasure in his injury, and an appeal to public opinion, on any occasion sufficiently important to involve a question of the interests of society, at once calls forth general condemnation of the selfish act as a real injustice.