Avicenna's legacy in classical psychology is primarily embodied in the Kitab al-nafs parts of his Kitab al-shifa (The Book of Healing) and Kitab al-najat (The Book of Deliverance). These were known in Latin under the title De Anima (treatises "on the soul").[dubious – discuss] Notably, Avicenna develops what is called the "flying man" argument in the Psychology of The Cure I.1.7 as defense of the argument that the soul is without <answer>quantitative extension</answer>, which has an affinity with Descartes's cogito argument (or what phenomenology designates as a form of an "epoche").
In an argument by Avicenna, the soul is without what?
quantitative extension