Abstract
In the Author’s Introduction to the first edition of Origin of Species, Charles Robert Darwin (1809–1882) mentioned he was dealing with his ideas on the origin of species since he returned from the voyage of the Beagle. Besides that, he intended to publish them in 2 years. Nevertheless, it did not happen. Several years later, when he was still dealing with his manuscript, in 1858, Darwin received a memoir from Alfred Russel Wallace (1823–1913) with the same general conclusions as him. Due to this, he published The Origin of Species the following year. Before the Origin (1859), Darwin and Wallace published their ideas in the Linnean Society of London journal. This chapter discusses Wallace’s ideas trying to detect to what extent they were similar to Darwin’s in their papers published in 1858. The analysis concluded that despite the sequence differences, both authors’ contributions are coherent. Although some terms or expressions are different, their connotation is the same. Both referred to the “struggle for existence” in nature, although Darwin did not use this expression. Wallace, contrary to Darwin, did not use the words “natural selection” but referred to a principle whose connotation is the same. Wallace and Darwin agreed that species exist first as varieties. Both of them admitted the principle of divergence. In short, their main ideas were similar, as they realized in 1858.