Suggestion is usually said to be of two kinds.

The first is hetero-suggestion, in which the self-realizing idea is received either wittingly or unwittingly from the outer world.

During the whole of our conscious lives for good or evil we are at the mercy of such hetero-suggestions, which are being made to us at every moment by our environment; and they form, as we shall afterwards see, a dominant factor in corporate religious exercises.

The second type is auto-suggestion.

In this, by means of the conscious mind, an idea is implanted in the unconscious and there left to mature.