 It would seem, therefore, that philosophers found no problems in Euclid’s Elements, but Hume, d’Alembert, and others of an empiricist persuasion qualified the applicability of the theorems on the grounds that the objects of geometry might have no corresponding objects in the world. Philosophers more open to the idea of a wide range of certain knowledge (as, for example, Kant) could grant geometrical theorems the status of a priori truths that cannot be other than they are.