"Everyone carries a shadow, and the less it is known consciously, the blacker and denser it is… Beneath the surface we are suffering from a deadly boredom that makes everything seem meaningless and empty… to find renewal means to descend into one's darkness."
—quotes from Carl Jung
There was a man who was so disturbed by his own shadow that he was determined to lose it for good. So he got up and ran. But his shadow kept up with him, and so he ran faster and faster until the exertion took its toll and he dropped dead. If he had simply stepped into the shade, sat down and stayed still [meditated], his shadow would have vanished. —Chuang Tzu, The Way
Each individual has a reservoir of behaviors, desires and experiences—the shadow—that are rejected and disavowed during the hunt for acceptance and approval from others, for we humans are essentially pack animals, built to socialize, interact, seek and establish security from each other, just as fish are built to survive in water. The world informs us quickly of which conduct it prizes and which behavior it deems abhorrent. In our relentless search for connection and acceptance, primitive instincts and unpopular practices that would interrupt our 'admittance into the social club' are suppressed. The weeding starts during childhood socialization and continues throughout adult life. In short, shadow qualities are dominated and marginalized by the conscious mind; many of us develop a host of essentially unnatural, performative practices to win love and support from our environs.
It should be understood that many aspects of the shadow are indeed negative and destructive; the mind is capable of an limitless array of selfishness, dishonesty, plotting maliciousness, rage and arrogance, to name a few less than stellar traits. But there are many positive aspects which are also repressed and concealed in one's shadow: for example, creative impulses may be poorly received in unimaginative families; a natural cluster of behaviors that fall outside of gender expectations may be concealed to find love in our largely homophobic climate. The more we reject, the greater a sense of emptiness and lack of fullness; judging and rejecting our shadow elements when they appear—“I should get more done; why am I so lazy!"—only nourishes low self-esteem and a sense of unworthiness.
While constantly seeking approval means we must try to contain the shadow, such a task is not feasible over the course of lifetime. Like someone running away from their own (literal) shadow, it leads to stress and suffering. The way of full integration is to consciously receive and give space—without being driven to act out on—one's shadow attributes. We could refer to this as "Dr. Jekyll,"—our conscious, daylight awareness—investigating and opening to the nature of "Mr. Hyde" (our shadow domain). If Jekyll continues to suppress Hyde, then the latter has little choice but to burst out through the cracks of consciousness, during dreams, times of stress, when provoked by others, wrecking havoc and leaving chaos as a result. Indeed, the process of individuation requires our conscious awareness to cast a light into the dim basement of the mind, revealing what's been stored and abandoned, courageously confronting, as it were, what lurks in the darkness.
The key to skillfully assimilating one's shadow is to become aware of shadow impulses and experiences without identification. This is what we practice in Insight Meditation, fueled by mindfulness: We turn towards each sensation, image, memory, impulse, etc that arises, and observe without resistance or enactment. Rather, we feel the emotional energy asking to be given attention, holding what arises with compassion and acceptance, rather than pushing it back into the dark compartments of the mind. During this work we are careful not to claim anything that appears as our "true nature" or "core self." Just as Jung reported, non-identification is the life saver which allows us to view what's repressed without fully descending into unskillful impulses that could easily disrupt and impair our mundane, day to day lives and projects.
When we return to the repressed, we become aware of impulses in ourselves for which we've criticized others; its work that inevitably requires us to become more forgiving of the people in our lives. They too have their shadows with which they wrestle, sometimes unsuccessfully. Rather than spending life running from our own shadows, we can find a nice spot of shade beneath our favorite bodhi tree and relax for awhile.