Darwinism originally included the broad concepts of transmutation of species or of evolution which gained general scientific acceptance when Charles Darwin published On the Origin of Species, including concepts which predated Darwin’s theories, but subsequently referred to specific concepts of natural selection, the Weismann barrier or in genetics the central dogma of molecular biology.
Though it usually refers strictly to biological evolution, the term has been used by creationists to refer to the origin of life, and has even been applied to concepts of cosmic evolution, both fields which have no connection to Darwin’s work. It is therefore considered the belief and acceptance of Darwin’s, and his predecessors, work in place of other theories including divine design and extra-terrestrial origins.
The meaning of “Darwinism” has changed over time, and varies depending on its context. In the United States, the term “Darwinism” is often used by creationists as a pejorativeterm in reference to beliefs such as atheistic naturalism, but in the United Kingdom the term has no negative connotations, being freely used as a shorthand for the body of theory dealing with evolution, and in particular, evolution by natural selection.
The term was coined by Thomas Henry Huxley in April 1860, and was used to describe evolutionary concepts in general, including earlier concepts such as Spencerism. Many of the proponents of Darwinism at that time, including Huxley, had reservations about the significance of natural selection, and Darwin himself gave credence to what was later called Lamarckism.
Darwinism of August Weismann gained few supporters in the late 19th century. During this period, which has been called “the eclipse of Darwinism”, scientists proposed various alternative evolutionary mechanisms which eventually proved untenable. The development of the modern evolutionary synthesis from the 1930s to the1950s, incorporating natural selection with population genetics and Mendelian genetics, revived Darwinism in an updated form.
While the term has remained in use amongst scientific authors when referring to modern evolutionary theory, it has increasingly been argued that it is an inappropriate term for modern evolutionary theory. For example, Darwin was unfamiliar with the work of Gregor Mendel, and as a result had only a vague and inaccurate understanding of heredity. He naturally had no inkling of yet more recent developments and, like Mendel himself, knew nothing of genetic drift for example.