Spontaneous generation refers to the belief that living organisms can arise from non-living matter. However, since this theory has been disproven, there are several synonyms that can be used in its place. These include abiogenesis, autogenesis, and equivocal generation. Each of these terms refers to the concept that life could arise from non-life, but they are more commonly used today to describe the study of the origin of life on Earth. Other phrases that could be used as synonyms for spontaneous generation might include primitive life-form evolution or even self-organized complexity, which are more modern and scientifically plausible ways of considering the development of early life.