Appreciating Sadness

In The Mastery of Love don Miguel Ruiz writes "Everything is made by Love, by Life. Even fear is a reflection of love...." This gave me pause while feeling true. I put the book down to happily reflect on this novel piece of wisdom. I'm so used to seeing fear as the enemy of a loving relationship, an enemy of loving myself. But, it's true. It's originally the body's mechanism for protecting the organism from danger. It fuels the flight response. It is just that the human mind tends to accrus a lot of baggage and react with fear unnecessarily. The same holds for anger, it is also an expression of love, a protective response.
What about sadness? What is the biological advantage of sadness? As honed as our bodies are, sadness evolved for a reason, and in a search for the answer, a few different ideas came up.
Sadness/depression lead to great art. Joni Mitchell calls sadness "the sand that makes the pearl." Psychologist James Hillman observes: "Depression opens the door to beauty of some kind." Over recorded history, many of the commonly considered greatest artists were quite depressed, many attempted or committed suicide. One theory is that sadness is the inspiration for art. I've personally found that if I'm a little down, I can turn to creating art as a pick-me-up. The act of making art puts me in a state of flow (a la Mihaly Czikszentmihalyi) or helps me be in the present moment, the now. Many folks in happiness theory talk about how being in the now is the truest way to find happiness, so perhaps sadness encourages people to seek out flow activities.
Melancholia is part of the whole mental health picture. Some experts, including Jung, concluded that melancholia is essential to mental health. More on this topic can be found in Eric G. Wilson's book Against Happiness: In Praise of Melancholy. The theory here is that the psyche needs a full complement of emotions in order to be complete. To me this feels a bit taoist, recalling to mind Lao-Tzu's line from the Tao Te Ching that I've seen translated as: "Misery is but the shadow of happiness / Happiness is but the cloak of misery." The two are needfully balanced sides of the same coin. It also points to the idea that happiness may be relative and the full cycle, including sadness is also needed.

Sadness is a focusing tool. This is the most convincing argument that I've seen. "... depression is nature’s way of telling you that you’ve got complex social problems that the mind is intent on solving." From Scientific American's "Depression's Evolutionary Roots". This theory essentially sets up this chain: Sadness results from social problems. Social problems are dangerous to primates and village societies, our evolutionary roots, because if you don't fit into the group, you don't get protection, food, shelter, status, and reproductive power within your society. Essentially, you don't survive in harsh conditions. Sadness, in turn, releases a chemical in the brain that blocks the 5HT1A receptor which binds to seratonin. A few other effects concur with this, including tendency for creative rumination, increased ability to focus, decreases in sex drive, thirst, hunger, and pain-sensitivity. So, essentially, it provides the brain with creativity and focus that it needs for problem solving while reducing the drives for distractions, allowing the brain to figure it's way out of the social mess as fast as possible.
For the past several months, I've kept this in mind and have been able to appreciate all of my emotions a bit more, seeing them for the beneficial sides that they have. When I find myself a little sadness, I can treat this as a cue to examine my state, determine the cause of my sadness at a social level, and see if I can harness my increased focus and creativity to do my best and most creative work and to solve the problem that I am facing.