An Elegant Defense

Commonly cited examples of multiple independent discoveries are the independent formulation of calculus by Isaac Newton and Gottfried Wilhelm Leibniz in the 17th century; the independent discovery of oxygen by Carl Wilhelm Scheele, Joseph Priestley, Antoine Lavoisier and others in the 18th century; and the theory of the evolution of species by natural selection, which was independently proposed by Charles Darwin and Alfred Russel Wallace in the 19th century.