Centering Prayer does not "empty the mind" or exclude other forms of prayer. It is not a "technique" that automatically creates "mysticism" or a means "to reach an altered state of consciousness."
It is important not to confuse Centering Prayer with certain Eastern techniques of meditation such as Transcendental Meditation. The use of the sacred word in Centering Prayer does not have the particular calming effect attributed to the TM mantra. Nor is the sacred word a vehicle leading to the spiritual level of one's being as it is in TM. There is no cause-and-effect relationship between using the sacred word and arriving at some altered state of consciousness. The sacred word is merely the symbol of the consent of one's will to God's presence and action within based on faith in the doctrine of the Divine Indwelling. The sacred word is simply a means of reaffirming our original intention at the beginning of our period of prayer to be in God's presence and to surrender to the divine action when we are attracted to some other thought, feeling or impression.
Throughout the period of Centering Prayer, our intention predominates: the movement of our will to consent to God's intention, which according to our faith, is to communicate the divine life to us. Hence, unlike TM, Centering Prayer is a personal relationship with God, not a technique.