lusions
will produce good results.

CHAPTER IV

INWARDNESS OF ENVIRONMENT

[Sidenote: _Factors of Success or Failure_]

The aspect of the sense-perceptive process that deals with the
relation of mind to environment is of greatest practical value.

Look at this subject for a moment and you will see that the world
in which you live and work is a world of your own making. All the
factors of success or failure are factors of your own choosing and
creation.

If there is anything in the world you feel sure of, it is that you
can depend upon the "evidence of your own senses," eyes, ears,
nose, etc. You rest serene in the conviction that your senses
picture the world to you exactly as it is. It is a common saying
that "Seeing is believing."

[Sidenote: _Should Seeing Be Believing?_]

Yet how can you be sure that any object in the external world is
actually what your sense-perceptions report it to be?

You have learned that a countless number of physical agencies must
intervene before your mind can receive an impression or message
through any of the senses.

Under these conditions you cannot be sure that your impression of
a green lamp-shade, for instance, comes through the same sort of
etheric and cellular activities that convey a picture of the same
lamp-shade to the brain of another. If the physical agencies through
which your sense-impressions of the lamp-shade filter are not
identical with the agencies through which they pass to the other
person's brain, then your mental picture and his mental picture
cannot be the same. You can never be sure that what both you and
another may describe as green may not create an entirely different
impression in your mind from the impression it creates in his.

Other facts add to your uncertainty. Thus, _the same stimulus_
acting on _different organs_ of sense will produce _different
sensations_. A blow upon the eye will cause you to "see stars"; a
similar _blow_ upon the ear will cause you to _hear_ an explosive
sound. In other words, the vibratory effect of a _touch_ on eye
or ear is the same as that of _light_ or _sound_ vibrations.

[Sidenote: _Hearing the Lightning_]

The notion you may form of any object in the outer world depends
solely upon what part of your brain happens to be connected with
that particular nerve-end that receives an impression from the
object.

You _see_ the sun without being able to _hear_ it because the only
nerve-ends tuned to vibrat