Perception has already been partially defined. So-called 'external
objects' are forms excited in our consciousness by pressure of other
minds. The great permanent 'world' is due to the action of a cosmic
mind with which we are intimately associated throughout our physical
life.
Objects have a totally different sort of existence from minds, for
whereas the latter are--at least relative to objects--self-existent,
the former have no existence except during the act of perception. If
minds could be all moved asunder from each other the whole objective
world would disappear, yet the universe would be as full as before,
for sensation occupies no room.
The appearances we interpret as distance are due to variations in the
pressure or stimulus producing the object.
It will be convenient to call the more active mind _Noumenon_, the
perceiving mind _Subject_. The mind that is subject on one occasion
may be noumenon at another, and conversely. The true antithesis to
subject is not object, but noumenon. Object has no antithesis, unless
it be nonentity.
It is specially to be noticed that an object is not the _cause_ of a
sentiment. The knife we see or handle is not the cause of the pain it
may inflict if driven into our flesh. Pains and pleasures signify that
the noumenal action is powerful enough not only to excite objects in
the intellect, but to penetrate inwards and excite sentiments also. It
is the noumenon that causes both object and sentiment, as far as
the energy exerted is concerned, but the variation of plasma in the
subject is also essential to the distinction of object and sentiment.
The subject is not quite passive in perception. No consciousness
takes place unless the subject is charged with energy. Further, since
consciousness is confined to the Self and not inherent in the plasma,
we perceive only such vibrations as reach the Self. If the Self is
absorbed in one part of the mind, vibrations may take place in other
parts without being noticed. The more energy we concentrate at the
point or surface of contact (Attention), or otherwise bring to bear on
the plasmic vibration, the more vivid is the object.
The fixing or circumscribing of attention so as to break up our
experience into distinct things or objects is an acquired art, whence
we may infer that the intellectual experience of infancy is a vague
whitish surface, not clearly distinguished by colour or movement.
Kant and other philosophers admit that objects are caused by noumena,
but insist that we can never know or conceive what a noumenon is.
Why not? Each of us knows himself to be the noumenon of many
phenomena; he has no doubt that many other phenomena are caused by
minds like himself, and it is easy to extend this principle to all
phenomena whatever. They are all caused by minds more or less like
human minds. This is a useful conclusion, although we are not able to
imagine very accurately the mind of an insect or of a being of cosmic
dimensions. It is not necessary we should, but the most general
inference of this sort is better than none at all, and better than the
notion that phenomena are self-existent and self-moving.
Although simple and intelligible when stated in the abstract,
perception is difficult to work out in detail. Objections start up on
every side, and it requires the utmost patience to reduce them to
what they are--_inferences_ from the realism we are supposed to have
discarded. It is only when we try to dislodge realism wholly and
consistently that we find how fast its hold upon our intellect is.
Critics who profess to treat Berkeley's substantialism seriously and
sympathetically, constantly bring up against it arguments of the most
naively realistic kind. They have no adequate conception how enormous
is the revolution in thought involved in substituting substantialism
for realism. It is a complete dissolution of the natural thought and
belief; it means the construction of a new heaven and a new earth with
laws to which we have been hitherto unaccustomed. The old science is
of little or no use to us as substantialists.
Philosophy is not an advance or correction of science. In so far
as the latter claims to be absolutely or philosophically true,
substantialism abolishes it in dispensing with the notions of real
matter and real space. Hence it is quite irrelevant to point out that
substantialism is inconsistent with (say) the doctrine of physical
evolution. This theory, though so new, is now often referred to as
axiomatically true, whereas it is an inference, the evidence for
which, even to many realists, is far from conclusive. Whether it be
considered true or not in science, physical evolution is quite untrue
in philosophy.