Biogenesis is the production of new living organisms or organelles. The law of biogenesis, attributed to Louis Pasteur, is the observation that living things come only from other living things, by reproduction (e.g. a spider lays eggs, which develop into spiders). That is, life does not arise from non-living material, which was the position held by spontaneous generation. This is summarized in the phrase Omne vivum ex vivo, Latin for "all life [is] from life." A related statement is Omnis cellula e cellula, "all cells [are] from cells;" this observation is one of the central statements of cell theory.