JuLy 24, 1902] 
NATURE 301 
and that the phenomena of the inanimate or physical and of the 
living world are fundamentally identical? The progress of 
physiological science has greatly increased the impetus towards 
the adoption of this thought as the cardinal dogma of the new 
faith, because the work of physiologists has been so devoted to 
the physical and chemical phenomena of life that the conviction 
is widespread that all vital phenomena are capable of a physical 
explanation. Assuming that conviction to be correct, it is easy 
to draw the final conclusion that the physical explanation suffices 
for the entire universe. As to what is, or may be, behind the 
physical explanation, complete agnosticism is, of course, the only 
possible attitude. Such in barest, but I believe correct, outline 
is the history of modern monism, the doctrine that there is but 
one kind of power in the universe. 
It is evident that monism involves the elimination of two con- 
cepts, God and consciousness. It is true that monists sometimes 
use these words, butit is mere jugglery, for they deny the concepts 
for which the words actually stana. Now consciousness is too 
familiar to all men to be summarily cast aside and dismissed. 
Some way must be found to account for it. From the monistic 
standpoint there is a choice between two possible alternatives, 
either consciousness is a form of energy, like heat, &c., or it is 
merely a so-called epiphenomenon. As there is no evidence that 
consciousness is a form of energy, only the second alternative 
is in reality available, and in fact has been adopted by the 
monists. 
It is essential to have a clear notion of what is meant by an 
epiphenomenon. Etymologically the word indicates something 
which is superimposed upon the actual phenomenon. It desig- 
nates an accompanying incident of a process, which is assumed 
to have no causal relation to the further development of the 
process. In practice it is used chiefly in regard to the relation 
of the mind or consciousness to the body, and is commonly em- 
ployed by those philosophers who believe that consciousness has 
no causal relation to any subsequent physiological process. 
For many years I have tried to recognise some actual idea 
underneath the epiphenomenon hypothesis of consciousness, but 
it more and more seems-clear to me that there is no idea at all, 
and that the hypothesis is an empty phrase, a subterfuge, which 
really amounts only to this: we can explain consciousness very 
easily by merely assuming that it does not require to be ex- 
plained at all. Is not that really the confession made by the 
famous assertion that the consciousness of the brain’no more 
requires explanation than the aquosity of water ? : 
Monism is not a strong system of philosophy, for it is not so 
much the product of deep and original thinking as the result of 
a contemporary tendency. It is not the inevitable end of a 
logical process, because it omits consciousness, but rather an 
incidental result of an intellectual impulse. Its very popularity 
betokens its lack of profundity, and its delight in simple formulz 
is characteristic of that mediocrity of thought which has much more 
ambition than real power and accepts simplicity of formularisa- 
tion as equivalent to evidence. It would seem stronger, too, if 
it were less defended asa faith. Strong partisans make feeble 
philosophers. 
Consciousness ought to be regarded as a biological pheno- 
menon, which the biologist has to investigate in order to in- 
crease the number of verifiable data concerning it. In that 
way rather than by speculative thought is the problem of con- 
sciousness to be solved, and it is precisely because biologists are | 
beginning to study consciousness that it is becoming, as I said 
in opening, the newest problem of science. 
The biologist must necessarily become more and more the 
supreme arbiter of all science and philosophy, for human know- 
ledge is itself a biological function, which will become compre- 
hensible just in the measure that biology progresses and brings 
knowledge of man, both by himself and through comparison 
with all other living things. We must look to biologists for 
the mighty generalisations to come rather than to the 
philosophers, because great new thoughts are generated more 
by the accumulation of observations than by deep meditation. 
To know, observe. Observe more and more, and in the end 
you will know. A generalisation is a mountain of observations ; 
from the summit the outlook is broad; the great observer climbs 
to the outlook while the mere thinker struggles to imagine it. 
The best that can be achieved by sheer thinking on the data of | 
ordinary human experience we have already as our glorious in- 
heritance. The principal contribution of science to human 
progress is the recognition of the value of accumulating data, 
which are found outside of ordinary human experience. 
NO. 1708, VOL. 66] 
| received at other times. 
Twenty-three years ago, at Saratoga, I presented before the 
meeting of this Association—which I then attended for the first 
time—a paper ‘‘On the Conditions to be Filled by a Theory of 
Life,” in which I maintained that before we can forma theory of 
life we must settle what are the phenomena to be explained by 
it. So now, in regard to consciousness, it may be maintained that 
for the present it is more important to seek additional positive 
knowledge than to hunt for ultimate interpretations. We wel- 
come, therefore, especially the young science of experimental 
psychology, which, it is gratifying to note, has made a more 
auspicious start in America than in any other country. It com- 
pletes the circle of the biological sciences. It is the department of 
biology to which properly belongs the problem of consciousness, 
The results of experimental psychology are still for the most part 
future. But I shall endeavour to show that we may obtain some 
valuable preliminary notions concerning consciousness from our 
present biological knowledge. 
We must begin by accepting the direct evidence of our own 
consciousness as furnishing the basis. We must, further, accept 
the evidence that consciousness exists in other men essentially 
identical with the consciousness in each ofus. The anatomical, 
physiological and psychological evidence of the identity of the 
phenomena in different human individuals is to a scientific mind 
absolutely conclusive, even though we continue to admit cheer- 
fully that the epistemologist rightly asserts that no knowledge is 
absolute, and that the metaphysician rightly claims that ego is 
the only reality and everything else exists only as ego's idea, 
because in science, as in practical life, we assume that our 
knowledge is real and is objective in source. 
For the purposes of the following discussion. we must define 
certain qualities or characteristics of consciousness. The most 
striking distinction of the processes in living bodies, as compared 
with those in inanimate bodies, is that the living processes have 
an object—they are teleological. ' The ‘distinction is so con- 
spicuous that the biologist can very often say why a given 
structure exists or w/y a given function is performed, but ow 
the structure exists or how the function is performed he can tell 
very imperfectly—more often not at all. Consciousness is only 
a particular example, though an excellent one, of this pecu- 
liarity of biological knowledge ; we do not know what it is; 
we do not know how it functions; but we do know why it 
exists. Those who are baffled by the elusiveness of conscious- 
ness, when we attempt to analyse it, will do well to remember 
that all other vital phenomena are in the last instance equally 
and similarly elusive. 
In order to determine the teleological value of consciousness 
we must endeavour to make clear to ourselves what the essential 
function is which it performs. As I have found no description 
or statement of that function which satisfied me, I have 
ventured, perhaps rashly, to draw up the following new 
description :— 
The function of consctousness 7s to dislocate in time the re- 
actions from sensations. 
In one sense this may be called a definition of consciousness, 
but inasmuch as it does not tell what consciousness is, but only 
what it does, we have not a true definition, but a description 
of a function. The description itself calls for a brief explana- 
tion. We receive constantly numerous sensations, and in response 
to these we do many things. These doings are, comprehensively 
speaking, our reactions to our sensations. When the response 
to a stimulus is obviously direct and immediate, we call the 
response a reflex action ; but a very large share of our actions 
are not reflex, but are determined in a far more complicated 
manner by the intervention of consciousness, which may do one 
of two things, first, stop a reaction, as, for example, when some- 
thing occurs calling, as it were, for our attention and we do not 
| give our attention to it; this we call conscious inhibition ; it 
plays a great 7d/e in our lives, but it doesnot mean necessarily 
that inhibited impressions may not survive in memory and’at a 
later time determine the action taken ; in such cases the potential 
reaction is stored up. Second, consciousness may evoke a reaction 
from a remembered sensation and combine it’ with sensations 
In other words, consciousness has a 
selective power, manifest both in ‘choosing from sensations 
received at the same time and in combining sensations received 
at different times. It can make synchronous impressions 
dyschronous in their effects, and dyschronous impressions syn- 
chronous. But this somewhat formidable sentence merely para- 
phrases our original description :—The function of consciousness 
is to dislocate in time the reactions from sensations. 
