The Mind and the Brain | Page 8

our own kind; an
imaginary and transposed sensation, when we are studying anatomy by
means of an anatomical chart; but still a sensation. It is by the
intermediary of our nervous system that we have to perceive and
imagine what a nervous system is like; consequently we are ignorant as
to the modification impressed on our perceptions and imaginations by
this intermediary, the nature of which we are unable to grasp.
Therefore, when we attempt to understand the inmost nature of the
outer world, we stand before it as before absolute darkness. There
probably exists in nature, outside of ourselves, neither colour, odour,
force, resistance, space, nor anything that we know as sensation. Light
is produced by the excitement of the optic nerve, and it shines only in
our brain; as to the excitement itself, there is nothing to prove that it is
luminous; outside of us is profound darkness, or even worse, since
darkness is the correlation of light. In the same way, all the sonorous
excitements which assail us, the creakings of machines, the sounds of
nature, the words and cries of our fellows are produced by excitements
of our acoustic nerve; it is in our brain that noise is produced, outside
there reigns a dead silence. The same may be said of all our other
senses.
Not one of our senses, absolutely none, is the revealer of external
reality. From this point of view there is no higher and no lower sense.
The sensations of sight, apparently so objective and so searching, no
more take us out of ourselves than do the sensations of taste which are
localised in the tongue.
In short, our nervous system, which enables us to communicate with

objects, prevents us, on the other hand, from knowing their nature. It is
an organ of relation with the outer world; it is also, for us, a cause of
isolation. We never go outside ourselves. We are walled in. And all we
can say of matter and of the outer world is, that it is revealed to us
solely by the sensations it affords us, that it is the unknown cause of
our sensations, the inaccessible excitant of our organs of the senses, and
that the ideas we are able to form as to the nature and the properties of
that excitant, are necessarily derived from our sensations, and are
subjective to the same degree as those sensations themselves.
But we must make haste to add that this point of view is the one which
is reached when we regard the relations of sensation with its unknown
cause the great X of matter.[7] Positive science and practical life do not
take for an objective this relation of sensation with the Unknowable;
they leave this to metaphysics. They distribute themselves over the
study of sensation and examine the reciprocal relations of sensations
with sensations. Those last, condemned as misleading appearances
when we seek in them the expression of the Unknowable, lose this
illusory character when we consider them in their reciprocal relations.
Then they constitute for us reality, the whole of reality and the only
object of human knowledge. The world is but an assembly of present,
past, and possible sensations; the affair of science is to analyse and
co-ordinate them by separating their accidental from their constant
relations.
FOOTNOTES:
[Footnote 3: Connaissance.--The word cognition is used throughout as
the English equivalent of this, except in places where the context shows
that it means acquaintance merely.--ED.]
[Footnote 4: J. S. MILL, An Examination of Sir Wm. Hamilton's
Philosophy, pp. 5 and 6. London. 1865.]
[Footnote 5: A few subtle philosophers have returned to it, as I shall
show later in chapter iv.]
[Footnote 6: Thus, the perplexity in which John Stuart Mill finds

himself is very curious. Having admitted unreservedly that our
knowledge is confined to sensations, he is powerless to set up a reality
outside this, and acknowledges that the principle of causality cannot
legitimately be used to prove that our sensations have a cause which is
not a sensation, because this principle cannot be applied outside the
world of phenomena.]
[Footnote 7: See p. 18, sup.--ED.]
CHAPTER III
THE MECHANICAL THEORIES OF MATTER ARE ONLY
SYMBOLS
If we keep firmly in mind the preceding conclusion--a conclusion
which is neither exclusively my own, nor very new--we shall find a
certain satisfaction in watching the discussions of physicists on the
essence of matter, on the nature of force and of energy, and on the
relations of ponderable and imponderable matter. We all know how hot
is the fight raging on this question. At the present time it is increasing
in intensity, in consequence of the disturbance imported into existing
theories by the new discoveries of radio-activity.[8] We psychologists
can look on very calmly at these discussions, with that