He'll have reached the fourth stage of detachment when he's found his own way to start something new—with enthusiasm for the doing of it, rather than out of the need to prove something. You know you've reached that stage when thinking about your loss (or about the thing you desire) doesn't interfere with your normal feelings of well-being.
The three stickiest aspects of attachment are the excited desire we feel when we want something, the anxiety we feel about losing it, and the sense of hopelessness that can arise when we've failed to achieve it. Some of us tend to be more desire-driven, ruled by excitement and passion. Others tend to get more caught by anxiety, others by despair. But any of these feelings cut us off from happiness.
Even excitement, which we think of as a positive feeling, actually creates agitation inside you. (Think about how on edge you feel when there's something you want badly. Along with the excitement, there's always a layer of fear and anxiety, because some part of you fears you won't get what you want after all.) Desire, fear, and hopelessness are deeply embedded in our psyches, so whenever there's any remnant of attachment, we're going to feel their pull. We know we've begun to achieve real detachment when we can contemplate a situation without getting blindsided by one of these three feelings. This is the beginning of stage five. It's also the beginning of real freedom.
Detachment as Offering
However, detachment, at least in my experience, doesn't really work if we do it in a grim-faced way. I have huge respect for the warrior-Zen approach to the inner life, the one where you heroically renounce your weaknesses, tough out the hard stuff, perhaps use your sense of humor to give you the power to move forward. For me, that only leads to a kind of emotional deep freeze. So the way I ease myself toward detachment is to practice offering. I connect myself to that inner Presence that the texts of Vedanta call Being/Awareness/Bliss, and then I offer whatever I'm doing, whatever I'm intending or wanting, or whatever I'm trying to get free of, to that Presence. That's the time-honored method of the Bhagavad Gita.
Every tradition includes some form of offering, but for detachment practice, the two most powerful ways to offer are to dedicate your actions before and after you do them, and to offer up fears, desires, doubts, and obstructions into the hands of the one consciousness. Offering our actions helps train us to do things not for any particular gain or personal purpose, but simply as an act of praise, or gratitude, or as a way of joining our consciousness to the greater Consciousness. Offering desires, fears, and doubts loosens the hold they have over us, reminds us to trust in the invisible source of life, and ultimately shows us that the same Presence is both the source of our longings and the source of their fulfillment.
Here is what the practice of offering might look like.
First, call to mind the largest and most benign level of reality you can feel personally connected with, whether it is humanity, or some particular teacher or deity, or the sense of Oneness, or of the great collective of the natural world—humans, animals, plants, earth and air, stars and planets and space itself. Or simply become aware of your own Being, the Presence or energy that feels most essential to your life.
Once you've done this—and if you're not used to it, you may have to find a feeling sense or a symbolic form to use as a point of focus—then bring to mind the action you're about to do, or the outcome you're hoping to bring about.
Mentally make an offering of it to the Presence. You can say something like, "I offer this to the source of all, asking that it be accomplished in the best possible way." If your issue is a strong attachment, or something that disturbs you about yourself or your life or someone else, bring it to mind, and offer that, asking, "May there be balance and harmony in this situation," or "May things work out for the benefit of all," or "May things work out according to the highest good."
Once you've made the offering, let yourself linger in the feeling-state that arises, the inner space you've created inside yourself by making the offering. If what you're offering is something that you care about deeply—your desire for a particular relationship, or your wish for the well being of your own body or of someone you love—you may notice that you're reluctant to let go of this thing that you've offered. If that's the case, then offer it again. Keep offering it until you begin to feel a loosening of your identification with the action, with your fear or desire or anger or feeling of injustice.
Whenever you feel the clutch of attachment, offer it again.
One of the great boons of the practice of offering your actions, weaknesses, and desires is that it makes you more and more intimate with the Presence inside that acts through your actions. The nurturing force of that Presence is the only thing that really dissolves fears and attachments. The more we get to know that vast benign energy, the more we realize that it is the source of our power and love. And that's when our detachment becomes something greater—not detachment from desire or fear, but awareness that what we are is so large that it can hold all our smaller feelings inside itself, and still be completely free.