The Mind and the Brain | Page 9

selfish pleasure
we unavowedly feel when we see people fighting while ourselves safe
from knocks. We have, in fact, the feeling that, come what may from
the discussions on the essence of matter, there can be no going beyond
the truth that matter is an excitant of our nervous system, and is only
known in connection with, the perception we have of this last.
If we open a work on physics or physiology we shall note with
astonishment how the above considerations are misunderstood.
Observers of nature who seek, and rightly, to give the maximum of
exactness to their observations, show that they are obsessed by one
constant prejudice: they mistrust sensation.
A great part of their efforts consists, by what they say, in reducing the
rôle of sensation to its fitting part in science; and the invention of
mechanical aids to observation is constantly held up as a means of

remedying the imperfection of our senses. In physics the thermometer
replaces the sensation of heat that our skin--our hand, for
example--experiences by the measurable elevation of a column of
mercury, and the scale-pan of a precise balance takes the place of the
vague sensation of trifling weights; in physiology a registering
apparatus replaces the sensation of the pulse which the doctor feels
with the end of his forefinger by a line on paper traced with indelible
ink, of which the duration and the intensity, as well as the varied
combinations of these two elements, can be measured line by line.
Learned men who pride themselves on their philosophical attainments
vaunt in very eloquent words the superiority of the physical instrument
over mere sensation. Evidently, however, the earnestness of this eulogy
leads them astray. The most perfect registering apparatus must, in the
long-run, after its most scientific operations, address itself to our senses
and produce in us some small sensation. The reading of the height
reached by the column of mercury in a thermometer when heated is
accomplished by a visual sensation, and it is by the sight that the
movements of the balance are controlled; and that the traces of the
sphygmograph are analysed. We may readily admit to physicists and
physiologists all the advantages of these apparatus. This is not the
question. It simply proves that there are sensations and sensations, and
that certain of these are better and more precise than others. The visual
sensation of relation in space seems to be par excellence the scientific
sensation which it is sought to substitute for all the rest. But, after all, it
is but a sensation.
Let us recognise that there is, in all this contempt on the part of
physicists for sensation, only differences in language, and that a
paraphrase would suffice to correct them without leaving any trace. Be
it so. But something graver remains. When one is convinced that our
knowledge of the outer world is limited to sensations, we can no longer
understand how it is possible to give oneself up, as physicists do, to
speculations upon the constitution of matter.
Up to the present there have been three principal ways of explaining the
physical phenomena of the universe. The first, the most abstract, and

the furthest from reality, is above all verbal. It consists in the use of
formulas in which the quality of the phenomena is replaced by their
magnitude, in which this magnitude, ascertained by the most precise
processes of measurement, becomes the object of abstract reasoning
which allows its modifications to be foreseen under given experimental
conditions. This is pure mathematics, a formal science depending upon
logic. Another conception, less restricted than the above, and of fairly
recent date, consists in treating all manifestations of nature as forms of
energy. This term "energy" has a very vague content. At the most it
expresses but two things: first, it is based on a faint recollection of
muscular force, and it reminds one dimly of the sensation experienced
when clenching the fists; and, secondly, it betrays a kind of very natural
respect for the forces of nature which, in all the images man has made
of them, constantly appear superior to his own. We may say "the
energy of nature;" but we should never say, what would be
experimentally correct; "the weakness of nature." The word "weakness"
we reserve for ourselves. Apart from these undecided suggestions, the
term energy is quite the proper term to designate phenomena, the
intimate nature of which we do not seek to penetrate, but of which we
only wish to ascertain the laws and measure the degrees.
A third conception, more imaginative and bolder than the others, is the
mechanical or kinetic theory. This last absolutely desires that we
should represent to ourselves, that we should imagine, how phenomena
really take place; and in seeking for the property of