_Büchner._ You will admit, I presume, that “the brain is not merely the
organ of thought and of all the higher mental faculties, but also the sole
and exclusive _seat of the soul_. Every thought is produced in the brain,
every kind of feeling and sensation, exertion of the will, and voluntary
motion, proceeds from it” (p. 141).
_Reader._ Not exactly “from it,” but from the soul, as I have already
established; though certainly the brain is instrumental in all vital
operations. As to the brain being “the sole and exclusive” seat of the
soul I think that physiologists do not agree, and that philosophers have
something to object.
_Büchner._ It is now a recognized truth. “It took a long time before it
was recognized, and it is even to this day difficult for those who are not
physicians to convince themselves of its correctness” (_ibid._)
_Reader._ It must be difficult indeed; for although we have reason to
believe that the brain is, so to say, the central telegraphic office where
every intelligence from the other parts of the body is received, yet it is
but natural to suppose that there cannot be a central office if there are
no other offices destined to correspond with it. On the other hand,
philosophers teach that _the soul is the form of the body_; which implies
that there are other parts of our body, besides the brain, where the soul
must be present.
_Büchner._ “These philosophers are a singular people. They talk of the
creation of the world as if they had been present on the occasion; they
define the Absolute as if they had sat at its table for years; they babble
about the nothing and the something, the ego and non‐ego, the _per se_ and
_in se_, universals and particulars, perishability and absolute existence,
the unknown _x_, etc., etc., with a confidence as if a celestial codex had
given them exact information about all these ideas and things, and they
plaster up the simplest notions with such a confused mass of high‐sounding
and learned but incomprehensible words and phrases as to turn the head of
a rational man. But, in spite of all this, upon their metaphysical
eminence they are not unfrequently so far off from any positive knowledge
that they commit the most amusing blunders, especially in those cases in
which philosophy and science meet, and when the latter threatens to
destroy the results of metaphysical speculation. Thus almost all
philosophical psychologists have struggled with rare energy against the
theory of the seat of the soul in the brain, and continue in their
opposition without taking the least notice of the progress of experimental
science” (pp. 142, 143).
_Reader._ I am surprised, doctor, at your declamation against
philosophers. You have no right to denounce them either in general or in
particular. I admit that rationalistic philosophers richly deserve all the
contempt you can heap upon them, but it is not fair in you to attack them;
for they are better than you. To lay your own faults on the shoulders of
your opponents is an old trick. The burglar calls his victim a thief;
designing Freemasons always prate about Jesuitical machinations; and
writers whose philosophical baggage is as light as their pretensions are
high inveigh against those by whom they dread to be exposed, refuted, and
supplanted. Such is the case with you. While pretending to describe
others, you have made the portrait of yourself. It is certainly difficult
to find another man in the world who babbles with as much confidence as
you do about, or rather against, creation, the Absolute, and the unknown
x, etc., etc. Yet your opponents are not infallible, nor do they pretend
to be; but if they “commit the most amusing blunders,” it is not owing to
their “metaphysical eminence,” as you suppose, but rather to their
metaphysical incapacity. Science, you say, sometimes “threatens to destroy
the results of metaphysical speculation”; but you should have added that
metaphysical speculation oftentimes saves science from shipwreck; for
empiricism without philosophy is a ship without a rudder.
You denounce your adversaries as men who do not take “the least notice of
the progress of experimental science.” This is a calumny. In fact, you
yourself inform us that one of your adversaries is philosopher Fischer, a
man who not only took notice of the progress of experimental science, but
greatly contributed to such a progress by his own intelligent and
indefatigable labors. You cannot therefore pretend that such a man lacked
“positive knowledge.” Now, he says: “That the soul is immanent in the
whole nervous system is proved, as it feels, perceives, and acts in every
part thereof. I do not feel pain in a central part of the brain, but in a
particular spot and place.”
_Büchner._ “And yet what Fischer denies is undoubtedly the fact. The
nerves themselves do not perceive; they merely call forth sensations by
conducting the impressions received to the brain. We do not feel pain in
the place injured, but in the brain. If a nerve of sensation be divided in
its course to the brain, all the parts which are supplied by it lose their
sensibility, for no other reason than that the conducting of the
impression to the brain is no longer possible. Every man who has no
knowledge of physiological processes believes the feeling of hunger to be
in the stomach. This is not so; the brain alone makes us conscious of the
feeling. If the nerve uniting brain and stomach be divided, hunger is at
an end, nor does it return. Neither does anger arise in the liver, or
courage in the chest, but in the brain only” (pp. 143, 144). “Habit and
external appearance have led to the false notion that we feel in places
subjected to external irritation. Physiology calls this relation ‘the law
of eccentric phenomena.’ According to it, we falsely attribute the feeling
perceived in the brain to the place where the impression is made....
Persons who have lost their arms or legs by amputation often feel during
their whole lives, in atmospheric changes, pains in limbs which they no
longer possess. If all his limbs were removed, man would still feel them.
From these facts it can scarcely be doubted that there must exist in the
brain a topography by means of which the various sensations of the
different parts of the body arise. Every part of the body which can be
separately perceived must have a corresponding spot in the brain which in
some degree represents it in the forum of consciousness” (pp. 144, 145).
_Reader._ This answer, doctor, is not altogether satisfactory. “The
nerves,” of course, “do not perceive.” This I willingly admit; but neither
does the brain perceive; for it is the soul that perceives. The nerves
“merely call forth sensations by conducting the impressions received to
the brain.” This cannot be denied; but it does not prove the non‐existence
of the soul in the nervous system. Suppose that a pin or a thorn presses
the finger; before the impression can be transmitted from the finger to
the brain, its reception in the finger must give rise to a change of
relation between the soul and the finger itself; which would be
impossible, if the soul were not in the finger. For, if the soul is not in
the finger, the impression made by the thorn will consist of a merely
mechanical movement; and when this movement is communicated to the brain,
what sensation can be called forth? A sensation of pain? No; for mere
mechanical movement cannot produce a sense of pain, unless it is felt to
disagree with the living organism. Now, the pricking is not felt to
disagree with the brain, but with the finger. It is therefore in the
finger and not in the brain that we feel the pain; which shows that the
soul really is in the finger, and in every other part of the body in which
we may experience any sensation.
Your reason for pretending that “we do not feel pain in the place injured,
but in the brain,” is quite unsatisfactory. It is true that if a nerve of
sensation be divided in its course to the brain, all the parts which are
supplied by it lose their sensibility; but what of that? Those parts lose
their sensibility because they lose their sensitiveness; that is, because
the cutting of the nerve, by impairing the body, causes the soul to
abandon the organic parts supplied by that nerve. You argue that, if the
soul is not present in a given part of the body, when the nerve has been
injured, the soul was not present in that same part before the nerve was
injured. This inference is evidently wrong. The soul informs the organism,
and any part of it, as long as the organs are suitably disposed for the
vital operations, and abandons the organism, or any part of it, as soon as
the organs have become unfit for the vital operations. Hence, as you
cannot infer the non‐existence of the soul in the brain of a living man
from the non‐existence of the same in the brain of a corpse, so you cannot
infer its non‐existence in a part of the body before the cutting of the
nerve from its non‐existence in the same part after the nerve has been
cut.
The feeling of hunger, you say, is not in the stomach, because “if the
nerve uniting brain and stomach be divided, hunger is at an end.” Is not
this very curious? Men need none of your theories to know where they feel
hungry; and they not only _believe_, as you say, but also _experience_,
that their feeling of hunger is in the stomach. How can this be reconciled
with your theory? You try to discredit the common belief by observing that
we “have no knowledge of physiological processes.” This, however, is not
true; for although we may not possess your _speculative_ knowledge of
those processes, yet we have an _experimental_ knowledge of them, which
beats all your speculations. The simplest common sense teaches that a
theory contradicted by facts is worth nothing. Now, the fact is that we
experience the sensation of hunger in the stomach, and not in the brain;
and therefore no physiological theory that contradicts such a fact can be
of any value.
You pretend that “habit and external appearance have led to the false
notion that we feel in places subjected to external irritation.” This
assertion cannot be justified. Habits are acquired by repeated acts; and
to assume that habit leads us to a false notion is to assume that we are
cheated by our actual sensations; which is inadmissible. As to “external
appearances,” it is evident that they have nothing to do with the
question, as sensations are not external appearances, but internal
realities. Hence when we say that “we feel in places subjected to external
irritation,” we express a real fact of which we have experimental
evidence, and in regard to which no habit or external appearance can make
us err.
The fact that “persons who have lost their arms or legs by amputation
often feel during their whole life, in atmospheric changes, pains in limbs
which they no longer possess,” does not tend to prove that the brain is
the exclusive seat of the soul. Hence I dismiss it altogether. With regard
to your conclusion that “every part of the body which can be separately
perceived must have a corresponding spot in the brain which in some degree
represents it in the forum of consciousness,” I have not the least
objection against it; I merely add that no part of the body in which the
soul is not actually present can be represented in the forum of
consciousness. For if the soul is not in the finger when the thorn pricks
it, the soul cannot say, _I feel the pain_; it could only say, _I know
that a material organ, with which I have nothing to do, is being injured_.
The soul would, in fact, but receive a telegram announcing what happens in
some distant quarter. If a telegram comes to you from Siberia, announcing
twenty degrees of cold, do you feel the sensation of cold?
_Büchner._ Yet “the theory that the brain is the seat of the soul is so
incontrovertible that it has long been adopted in the rules of law in
regard to monstrosities. A monstrosity with one body and two heads counts
for _two_ persons; one with two bodies and one head, only for one person.
Monstrosities without brain, so‐called acephali, possess no personality”
(pp. 147, 148).
_Reader._ This is true; and therefore the soul certainly informs the
brain. But it does not follow that other parts of the body are not
informed. Hence your remark has no bearing on the question; and it remains
true that the soul, as the form of the body, is directly connected with
every part of the organism in which vital acts are performed.