There's a scientific basis from which we can "put off the old man with his deeds," Col. 3:9; as Paul says we must. And no matter how much of "the old man"—or a mortal sense of ourselves—we have been believing in, we can start doing this instantly.
It's valuable to remember that the new man—or Mind's ideal expression—is the only real man, and "the old man" an illusive view of true identity. The good that people express confirms the presence of the real man, Soul's spiritual idea.
While spiritual identity is always perfect, our exchanging a supposed mortal identity for the divine is not likely to be achieved in a moment (though we can begin in this moment), nor can we gain it merely by manipulating human thought. Our accepting the Christ, the perfect image of God, is the way we progressively attain this.
