act, without any ideation whatever. Thus if the cerebrum of a pigeon be removed, the animal is still capable of seeing and of hearing, but it obtains no idea from those senses. The mind, with the exception of perception, is lost!” Perception is not, therefore, connected with consciousness; for, according to Dr. Hammond, we may hear and see without knowing it. We do not deny that impressions may be made on the organs of sense without eliciting an act of consciousness, for which reason, indeed, ordinary language has reserved the use of words designating the function of organs for those cases where consciousness is elicited; for no one would dream of saying that he feels the prick of a pin or hears another speak without knowing it. A cadaver can perceive as well as a living subject, if we are to accept Dr. Hammond’s view; for we know that an image may be formed and retained by the retina after death, and this is all that is needed for perception. To explain all intercurrent difficulties, we have but to fall back on ganglia and evolution. At each step of the intellectual process a convenient ganglion exists which evolves just the sort of force requisite to produce the desired result, and thus we have a perfect system of psychology. Of the intellect he says: “In the normal condition of the brain the excitation of a sense, and the consequent perception, do not stop at the special ganglion of that sense, but are transmitted to a more complex part of the brain, where the perception is resolved into an idea.” Thus is the brain made the sole organ of thought. We have but to say, “A perception is resolved into an idea,” and in so many words we bound over difficulties which made
Plato, after much deep pondering, invent a theory of thought, yet regarded as a matchless monument of subtlety and sublimity, which taxed the subtle intellects of St. Augustine, St. Thomas, Leibnitz, and Kant, and which will, in all probability, continue to be an object of curious research to the end of time. If a child, beholding the changeful images of a kaleidoscope, should, prompted by the curiosity of youthful age, inquire the reason of this beautiful play of colors, surely no one would cynically answer him that one figure is resolved into another. Dr. Hammond slurs over the difficulty; for the vexing question is, How does the mind form an idea?—not, whether a ganglion is excited and evolves force, but how, on the occasion of such excitation, an idea, which is something altogether different from the excitation, is produced in the mind.
This question he not only fails to answer, but exhibits a woful depreciation of its scope and gravity. He continues: “Thus the image impressed upon the retina, the perception of which has been formed by a sensory ganglion, ultimately causes the evolution of another force by which all its attributes capable of being represented upon the retina are more or less perfectly appreciated according to the structural qualities of the ideational centre.” This sentence furnishes the keynote to the whole theory of material psychics, and leads us to inquire into its growth and history. When Bichat in France and Sir Charles Bell in England simultaneously discovered that a separate function was assignable to the anterior and posterior nerve-fibres projected from each intervertebral foramen; that the anterior possess the power of causing muscular contraction, the
posterior that of giving rise to sensation, they laid the foundation of the wonderful and beautiful though much-perverted doctrine of the localization of function. The experiments of Flourens, Claude Bernard, Beaumont, Virchow, and Kolliker multiplied similar discoveries and enlarged the significance of Bell’s and Bichat’s conclusions. To every ganglion its separate function is now sought to be assigned, and we have already alluded to the interesting facts which ataxic and amnesic aphasia have lately developed. The intimate relation thus manifested between particular portions of the brain-substance and the corresponding mental function, aroused and quickened curiosity to find out the nature and reason of this dependence. The materialist perceived in this doctrine of the localization of function a new weapon for attacking the spirituality of the soul, and was not slow to bring it into requisition. It was assumed that a reason for the difference of function in the different portions of the nervous structure would be found in the intimate texture of the nerve-tissues themselves; and the assumption, in so far as it is logical to suppose, that a difference in organization can alone account for a difference in the manifestation of power, was fair and plausible. All efforts were now directed towards such discoveries in the minute histology of the nervous system as would point to a connection between special ganglia and the functions performed by them. The microscope, indeed, brought to light many wonderful differences, but none sufficient to justify what is, therefore, but a mere assumption—the conclusion that the peculiar organization of certain portions of the nervous system is as much the efficient cause
of the functions with which they are connected as the sun is the cause of heat and light, and the summer breeze of the ripple on the harvest field. It was deemed unnecessary to look for an explanation of intellection and volition beyond the known or knowable properties of those portions of the nervous substance with which the processes in question are connected. If, it was argued, certain varying states of the inner coat of minute blood-vessels fitted them to select, some arterial blood, and others venous blood, and no one thought to invoke any other agency in determining the cause of the difference or of the function, why should we admit the existence of a distinct substance in accounting for mental phenomena, when structural differences just as palpable and obvious are at hand to explain them? In a word, not only difference of function was attributed to difference of structure, but this latter difference was held to be the sole cause and chief origin of the function itself. Dazzled by the brilliancy of their discoveries, and misled by a false analogy, many physiologists confounded condition with cause, and, having perceived that the manifestations of the mind are profoundly modified by the character of the medium through which they are transmitted, inferred that the medium generated the function. This confusion of condition with cause was further aided by the current false notion of cause. Following Hume and Brown, most modern men of science behold nothing else in the relation of cause to effect than a mere invariable antecedence and subsequence of events, which, of course, nullifies the distinction proper between indispensable condition and cause. With them that is cause on the occurrence
of which something else invariably follows; nor need we look for any other relation between the two. This doctrine, applied to the phenomena of the mind, could not but lead the discoverers of localized functions to downright materialism. They perceived that certain phenomena invariably proceeded in the same manner from certain portions of the nervous organism, and that any disturbance of the latter was attended by a marked change in the character of the phenomena with which it was connected. This invariability of antecedence and fluctuating difference of effect pointed unerringly, they thought, to structural differences in the nervous system as the efficient cause of all its functions. Applying this doctrine of causation to the process of intellection, we find how logically it sustains Dr. Hammond’s assertion that mind is an evolution of force from a special ganglion, since an excitation of the same ganglion is always followed by the same result—viz., a mental apprehension.
The invariability of sequence is all that is needed to establish ganglion in the category of causes, and ideation in that of effects.
We will now apply the same method of reasoning to a case in which the obvious distinction between cause and condition cannot fail to strike the most inattentive, and make manifest the sophistry of materialistic physiology. Should we stray into a minster filled with a grand religious light, and find chancel, nave, and pillar all radiant with purple and violet, soft amber and regal red, we would naturally look to the stained-glass window to discover the source of those warm tints and brilliant hues, and would seek to determine what in those party-colored panes gives rise to the
effects we admire. We first discover in each colored glass a peculiarity of structure which especially adapts it to the emission of its proper ray, and then note that the difference in the color of the rays depends on this same peculiarity of structure. The problem is solved. Since a structural peculiarity in the violet pane, for instance, fits it for the emission of its own ray, and so on with respect to red, yellow, and purple, why need we look for any other source of those colors? As we discover in each party-colored pane the cause of the difference in the color of the ray, we mistake the cause of the difference for the cause of the ray, and assume not only the difference of the ray to depend on the color of the transmitting medium, but deem that medium to be itself the sole source of the light. In like manner the speculative and transcendental physiologist finds in the adaptation of certain portions of the nerve-tissue to the production of specific functions a reason for referring the highest order of mental phenomena to the nervous system as their cause, forgetting that the adaptation in question may be but a mere condition modifying the manifesting power of the substance which is the true source of the phenomena. The observer who regards colored glass as the source of light, because he has been able to trace a connection and establish a relation between the color of the ray and the minute structure of the glass, differs in naught from theorists of Dr. Hammond’s stripe, who make nervous ganglia centres or sources of ideation because of the invariable production of the latter on the occasion of some excitation in the former. In both instances is committed the error of confounding condition with
cause, of mistaking the cause of a difference between two occurrences for the cause of the occurrences themselves.