Have you ever wondered what causes that warm glow inside, the sense of peace and exhilaration when walking through the woods or sitting by the ocean and watching the sunset? How about the beauty of a fresh snowfall clinging to trees, the smell and feel of the first warm day in spring, or the vistas of unspoiled prairies or mountain ranges? Watching animals in the wild or even the behavior and antics of our pets can affect us similarly. Virtually everyone is touched by such experiences even though we seem to be increasingly alienating and isolating ourselves from nature. Biologists call this phenomenon biophilia ? defined as the human need for and love of natural places.

As you canoe a beautiful, crystal clear stream, is not the mood changed when you come upon an old tire lurking in the depths? How about the beer bottle you trip over on your "wilderness" backpack adventure? Do the plastic bags entangling your bare feet as you stroll the beach not spoil the mood? What becomes of the view of the open prairie or desert with billowing factory smoke in the distance? Is the wonder of the ocean sunrise diminished by offshore derricks interrupting the horizon? Do you like the dead silence of the forest pierced with the distant sound of a chain saw?

The interjection of human activity into these natural settings spoils them. It can change the mood from peace, wonder and personal reflection to disgust, anger and a sense of futility. Tripping over a pop can in nature is like interrupting a beautiful symphony by starting up an un-muffled Harley Davidson.

On the other hand, the chaos of centuries of forest refuse strewn about is a thing of beauty. In contrast, human refuse and junkyards are ugly and repulsive. The reason for this double standard is that we are, at our core, part of nature ? not synthetics. Just as birds of a feather flock together, we bind to our own kind as well. Nature is our kind; synthetic and industrial artificiality is not.