Wilderness is generally defined as a natural environment on Earth that has not been modified by human activity. Wilderness areas are considered important for ecological study, conservation, solitude, and recreation. Wilderness is deeply valued for cultural, spiritual, moral and aesthetic reasons as well, some nature writers believe wilderness is vital for the human spirit and creativity. The word, "wilderness", derives from the notion of "wildness"; in other words that which is not controllable by humans. The word's etymology is from the Old English wildeornes, which in turn derives from wildeor meaning wild beast (wild + deor = beast, deer) (The Collins English Dictionary, 2000). From this point of view, it is the wildness of a place that makes it a wilderness. The mere presence or activity of people does not disqualify an area from being "wilderness." Many ecosystems that are, or have been, inhabited or influenced by activities of people may still be considered "wild." This way of looking at wilderness includes areas within which natural processes operate without human interference.