substantial.

We can surely never arrive at the nature of things from without. No
matter how assiduous our researches may be, we can never reach anything
beyond images and names. We resemble a man going round a castle seeking
vainly for an entrance and sometimes sketching the facades. And yet this
is the method followed by all philosophers before me.

The truth about man is that he is not a pure knowing subject, not a
winged cherub without a material body, contemplating the world from
without. For he is himself rooted in that world. That is to say, he
finds himself in the world as an _individual_ whose knowledge, which is
the essential basis of the whole world as idea, is yet ever communicated
through the medium of the body, whose sensations are the starting point
of the understanding of that world. His body is for him an idea like
every other idea, an object among objects. He only knows its actions as
he knows the changes in all other objects, and but for one aid to his
understanding of himself he would find this idea and object as strange
and incomprehensible as all others. That aid is _will_, which alone
furnishes the key to the riddle of himself, solves the problem of his
own existence, reveals to him the inner structure and significance of
his being, his action, and his movements.

The body is the immediate object of will; it may be called the
_objectivity of will_. Every true act of will is also instantly a
visible act of the body, and every impression on the body is also at
once an impression on the will. When it is opposed to the will it is
called pain, and when consonant with the will it is called pleasure. The
essential identity of body and will is shown by the fact that every
violent movement of the will, that is to say, every emotion, directly
agitates the body and interferes with its vital functions. So we may
legitimately say, My body is the objectivity of my will.

It is simply owing to this special relation to one body that the knowing
subject is an individual. Our knowing, being bound to individuality,
necessitates that each of us can only be one, and yet each of us can
know all. Hence arises the need for philosophy. The double knowledge
which each of us possesses of his own body is the key to the nature of
every phenomenon in the world. Nothing is either known to us or
thinkable by us except will and idea. If we examine the reality of the
body and its actions, we discover nothing beyond the fact tha