Origin of life and definition of life, from Buffon to Oparin.

Many theories on origin of life at the end of the XIXth century and the beginning of the XXth, generally use conceptions of life instead of explicit definitions of life. This paper presents ideas on the origin of life as studied by Buffon (1707-1788), Lamarck (1744-1829), Darwin (1809-1882), Huxley (1825-1895), Oparin (1894-1980) and Haldane (1892-1964). We show that their conceptions on the evolution of matter and life reveal their conceptions of life rather than their definitions of life.