An intimate relation exists between the soul's form and the forces and conditions external to this form.

There is therefore, at all times and on all planes, an intimate relation between the form occupied by the soul and the forces and conditions external to this form.

That is, the universe outside the body occupied by the soul affords various stimuli whose impact affect the body and is felt by the soul.

Both the body and the soul react to all such stimuli. In other words, after any particular experience, neither the body nor the soul is just the same as it was before.

Something is added to the soul by every experience it undergoes.

The form has changed in some respect. And the soul, or sum total of mental factors, also has changed. Something is added to the soul by every experience it undergoes.

Conditioning is the most important process to understand.

It is this factor which added to the soul determines how the organism will act in the presence of the same stimulus in the future."