Scientific socialism is the term first used by Friedrich Engels to describe the social-political-economic theory first pioneered by Karl Marx. The purported reason why this form of socialism is "scientific socialism" (as opposed to "utopian socialism") is that it is said to be based on the scientific method, in that its theories are held to an empirical standard, observations are essential to its development, and these can result in changes and/or falsification of elements of the theory.
Although the term socialism has come to mean specifically a combination of political and economic science, it is also applicable to a broader area of science encompassing what is now considered sociology and the humanities. The distinction between utopian and scientific socialism originated with Marx, who criticized the utopian characteristics of French socialism and English and Scottish political economy. Engels later argued that utopian socialists failed to recognize why it was that socialism arose in the historical context that it did, that it arose as a response to new social contradictions of a new mode of production, i.e. capitalism. In recognizing the nature of socialism as the resolution of this contradiction and applying a thorough scientific understanding of capitalism, Engels asserted that socialism had broken free from a primitive state and become a science. This shift in socialism was seen as complementary to shifts in contemporary biology sparked by Charles Darwin and the understanding of evolution by natural selection; Marx and Engels saw this new understanding of biology as essential to the new understanding of socialism, and vice versa.
Similar methods for analyzing social and economic trends and involving socialism as a product of socioeconomic evolution have also been used by non-Marxist theoreticians, such as Joseph Schumpeter and Thorstein Veblen.