According to the impermanence doctrine, human life embodies this flux in the aging process, the cycle of birth and rebirth (samsara), and in any experience of loss. This is applicable to all beings and their environs including devas (mortal gods). The Buddha taught that because conditioned phenomena are impermanent, attachment to them becomes the cause for future suffering (dukkha). Impermanence is intimately associated with the doctrine of anatta, according to which things have no fixed nature, essence, or self.