»889.] Psychology. 531 
sciousness is always the efifect or outcome of some underlying 
activity, never itself the manifesting substrate. 
The underlying vital matrix is perceived by us as the 
nerve-system of organic beings. And all the functional ac- 
tivities of this nerve-system contribute toward the production 
of the mental presence, though many phases of it may remain 
unconscious; and this not only from their not attaining a suffi- 
cient degree of intensity, but also by dint of normal disposi- 
tion (see " Space and Touch," Mind, No. XL.). 
When the term consciousness is used collectively for a 
series of mental states which we experience during an hour or 
a lifetime, it does not denote an actual phenomenon or verita- 
ble existent, but stands merely as a general name, in the same 
way as " animal " or " plant." 
The term "mind" signifies to most persons some active 
immaterial agent within us, capable of producing or manifest- 
ing conscious states. As I do not believe in such an agent, I 
can rightly speak of mind only adjectively, as when I say : 
" mental states," and then " mental " is really synonymous 
with "conscious." Or I can speak of it, at most, as an attri- 
bute of our being, as when I say, "our mentality," which is 
not synonymous with our "consciousness," as it includes also 
the unconscious working of the brain toward the production 
tal " as an opposite to " physical." This distinction is felt by 
every one to be legitimate. Yet it is incontestable that every- 
thing physical — all matter and all motion — is realized by us 
solely as perception of our own. We become aware of it as a 
peculiar kind of conscious event within our own mental pres- 
ence. A physical fact is, consequently, itself of mental con- 
sistency, for it forms part of our own consciousness. And the 
only essential difference between it and other constituents of 
our consciousness lies in the fact of its being aroused in us 
through compulsory sense-stimulation, while other conscious 
states arise in us without any compulsory influence working 
upon us from outside our own being. 
To become, however, fully alive to the radical contrast ob- 
taining between what we call a "physical" and what we call 
a " mental " fact, we need only realize that mental facts, as such, 
are entirely imperceptible through sensory channels, while it 
is the very characteristic of physical facts to be thus percepti. 
ble. I can touch your physical being, hear 
e, and 
