In Système d’Epicure (1750), La Mettrie presents a hypothesis on the origin and evolution of animals which owes much both to the fifth book of Lucretius’s poem and to Montaigne’s Apologie de Raimond Sebond. Claiming that Nature’s operations are as unintentional and as amoral as the play of children, the French physician argues against all teleological explanations of the physical constitution of living beings (man included). Nature’s first attempts at creating individual beings must therefore have been characterized by frequent mistakes, some of which are still to be seen in a few monstruous cases. Evolution is assured only through a process of trial and error, where the elimination of "unfit" combinations is due to the inability of specific animals to reach adulthood and give birth to offspring. The perfection of a living being is not to be evaluated by means of comparisons to a preexisting model but depends instead on the intensity of this being’s sexual needs, which compel it to seek pleasure and to develop its mental skills.
Keywords: La Mettrie, Lucrezio, finalismo, fisiodicea, edonismo