ABSTRACT
One of the most famous of philosophical thought experiments was projected in Plato's Republic. The philosophical point of Jean Buridan's hypothetical example is twofold: it serves to illustrate and indicate the idea of free will. It could be argued that the mere hypothesis of an arch-deceiver is just not good enough. And it is to exhibit the special care and providence that a benign God has bestowed upon reason and "the crown of creation". Rene Descartes was the grand master of thought experimentation. Even as Descartes taught that the essential properties of an individual object are those of its features that it retains invariant throughout the course of change within the manifold of space and time. So Roderick Chisholm proposed to see the essential properties of an object as those of its features that it retains invariant over change within the manifold of possibility.
