In helping people discern between spirits, I often consider St. Ignatius and his rules of discernment. Ignatius calls discernment simply the process of knowing one thing or idea from another.
When Ignatius talks about discerning different spirits, he refers to “discerning of spirits“. The phrase — “of spirits” — is that which is being discerned. That is, which spiritual realities are to be distinguished, one from the other.
Spirits are merely the stirrings of the heart — anxiety, fear, hope, joy, peace sadness and similar emotions — that influence our life of faith and our progress toward God.
Thus, helping people discern is helping them distinguish between spirits. In the words of Father Timothy Gallagher his book The Discernment of Spirits — An Ignatian Guide for Everyday Living, we help people “to distinguish between different kinds of spiritual stirrings in our hearts, identifying those that are of God and those that are not, in order to accept the former and to reject the latter.”