Numerous versions of orthogenesis (see table) have been proposed. Woodward was a leading advocate of orthogenesis. His evolutionary theory was a form of orthogenesis. Baer believed in a teleological force in nature which directed evolution (orthogenesis). These theories often combined orthogenesis with other supposed mechanisms. The concept of orthogenesis has never been widely favored in evolutionary biology. Osborn was a believer in orthogenesis; he coined the term "aristogenesis" for his theory. Orthogenesis was popular among paleontologists such as Henry Fairfield Osborn. Orthogenesis was seen to lie outside the methodological naturalism of the sciences. Orthogenesis was the belief that evolution travels in internally directed trends and levels.