Polygenesis refers to the idea that human beings originate not from a single common origin, but from several separately originating lines of descent. It exists in two forms, creationist and evolutionist. Polygenesis does not refer to one single theory, but rather a cluster of theories; most of those theories are not popular view among either school of thought. The opposite position is known as monogenesis.
 Creationist polygenesis
Creationist polygenesis claims that God did not create just a single first couple, Adam and Eve, from whom all humanity is descended, but rather many first couples. This however contradicts many verses in the Bible which say all humanity is descended from Adam and Eve.
One form of this theory is pre-Adamism: God created other human beings prior to Adam and Eve. The usual interpretation is that the creation of humans in Genesis 1 and Genesis 2 are two different accounts of the same event; by contrast, the Pre-Adamite interpretation is that Genesis 1 refers to a separate earlier creation of human beings, prior to Adam's creation in Genesis 2.
Another form of this theory is co-Adamism: God created other human beings at the same time as Adam and Eve, rather than prior to them.
Variations of this theory were popular among ancient Pagan thinkers, especially when the need came to respond to the Christian account of creation. It has also been favoured by a number of 20th century occult writers.
Pre-Adamism and co-Adamism have the advantage that they avoid the need for incestuous pairings in the first generation after Adam and Eve; on the other hand, they contradict many parts of the Bible. They also have often been interpreted in a racist manner — e.g., claiming that only a certain race or races (especially Caucasian) were descended from Adam and Eve, and the rest belong to another inferior creation. This of course ignores the fact that, since all human beings are interfertile with one another, so much time has passed that even if polygenesis were true, everyone now alive would be descended from Adam and Eve by this point. Since Romans 5 argues that Christ came as saviour to do right what Adam had been done wrong, this view then implies that Jesus only came to save Adam and Eve's descendants, and other races cannot be saved. But, although pre-Adamism and co-Adamism have often been used to justify racism, it is possible to give these views a non-racist interpretation.
 Evolutionist polygenesis
Evolutionary theory is inherently polygenetic, in the sense that it sees the evolution of one species out of another usually taking place within a defined population rather than a single pair of individuals. But the term polygenesis has been used to refer to the idea that humans evolved separately from several separate ancestor species, rather than out of one single ancestor species. That view is rejected by modern evolutionary theory, although in the past it has had its advocates. Likewise, this view has been used to try to justify racial supremacism, but at the same time it can be adopted in non-racist forms.
The term is also sometimes used to refer to the theory that life may have originated in multiple separate events of abiogenesis, at different places and times, rather than there being a single incident of abiogenesis from which all life is descended. See second genesis.
 Linguistic monogenesis vs. polygenesis
In linguistics, monogenesis vs. polygenesis concerns whether there was a single original language, spoken by all humankind, or if there were multiple original languages, spoken by different subsets of humanity. In evolutionary terms, this is the argument about whether language evolved once, or on multiple separate occasions. It is a separate question from the evolution of the underlying species. In biblical creationist terms, it is believed that Adam spoke an original language, which later developed in different directions — greatly helped along by divine intervention at Babel. On the other hand, a polygenist creationist may believe that each of the separate creations of original humans corresponded to a separate original language.
In Jewish thought, the traditional belief is that the language of Adam was Hebrew — although that differs from the views of modern linguistics, which sees Hebrew evolving out of a Proto-Afro-Asiatic language which was also the common of other languages such as Arabic, Aramaic, ancient Egyptian, Coptic, Akkadian, and the various Ethiopic languages. Others have suggested the Adamic language was different from Hebrew, and was some other language now lost — Joseph Smith, the founder of Mormonism, claimed to have been given some knowledge of this language by divine revelation.
Linguistic polygenesis would contradict controversial hypotheses that claim that all the world's major language families originate from one common original language, such as Nostratic. However, most linguists who criticise these theories do so, not from any commitment to linguistic polygenism, but simply on the basis that there is a lack of evidence to support them — even if all human languages descend from a common origin, critics of these hypotheses believe that knowledge of it has been lost to the mists of time, and cannot be reconstructed.
- Peter J. Bowler Theories of Human Evolution: a Century of Debate, 1844-1944 Johns Hopkins University Press, 1986
- Richard G. Delisle Debating humankind's place in nature, 1860-2000: The Nature of Paleoanthropology Pearson Prentice, 2007