What is sophistics ? What are the genuine reasons of philosophers'hostility, from Plato and Aristotle to Habermas and Badiou ? This text offers a new definition of sophistics as critique of mainstream ontology and a description of the efficiency of such a critical view, through a comprehensive explanation of the primitive scenery between Parmenides'Poem and Gorgias' Treatise of Non-being, and Aristotle's settlement of the principle of non-contradiction in book Gamma of Metaphysics.