MTD stands for Moralistic-Therapeutic-Deistic. It may or may not have originated with Mark Shea, but he uses it regularly.
Taken with what Fr. Jonathan Morris says about Faith-Hope-Love, an interesting overlay emerges. He says that Faith saves us from seeing too shallowly. What could be more shallow than Moralism, which believes natural goodness is the highest we can aspire to and all but ignores the spirit realm, where the holiness that is possible by God’s sanctifying grace is considered an unrealistic and unattainable ideal? Hope saves us from fear, anxiety, and shame. Those who rely solely on therapeutic techniques to overcome their fundamental woundedness will never fully escape fear and dread over the long haul. Love saves us from the prison of our selfish egocentrism. Deism says that God created the world like a Supreme Watchmaker, and then sat back to watch it operate in its predetermined way. In Deism, God is not Love nor does God lovingly intervene in our lives, continually inviting us and calling us to himself, or more properly to communion with the community of the Blessed Trinity. God is the engine of Love. If you are deistic, believing you must rely on self-help because God’s help is not coming, you will find yourself unable to love. You may think you love, but it will be the worldly sort of love that doesn’t last, because it is cut off from the power source, God.
Do you unknowingly have MTD tendencies? We likely all do.