Alchemy is an influential philosophical tradition whose early practitioners’ claims to profound powers were known from antiquity. The defining objectives of alchemy are varied; these include the creation of the fabled philosopher's stone possessing powers including the capability of turning base metals into the noble metals gold or silver, as well as an elixir of life conferring youth and immortality. Western alchemy is recognized as a protoscience that contributed to the development of modern chemistry and medicine. Alchemists developed a framework of theory, terminology, experimental process and basic laboratory techniques that is still recognizable today. But alchemy differs from modern science in the inclusion of Hermetic principles and practices related to mythology, religion, and spirituality.