The Jesuit father Ignace-Gaston Pardies, mathematician and physicist of some renown in his time, published in 1672 a Discours de la Connoissance des Bestes, famous then, but little known today. Amidst the mass of material on the general controversy of the souls of beasts, this work is outstanding for its brilliance, literary charm, and degree of originality. It is well worth examination, for its own merits and its bearings on the dispute in which it proved an influential contribution, and because of the curious fate to which the book was destined. For the Discourse, which went through numerous editions and caused considerable stir in the Republic of Letters was, although purporting to be a refutation of the Cartesian mechanistic view, reputed to be intended as a defense of that system. From Pardies' own day to the present age, uncertainty has existed as to how the treatise is to be classified.