عنوان مقاله [English]
Philosophical demarcation regarding sensible and non- sensible world was always a distinctive among philosophers since the inception of philosophy. The result of such demarcation was to build two different kinds of philosophical grouping. On the one hand, there were the materialist philosophers who considered the limit of existence up to sensible beings and on the other hand, there was philosophers who hold that the limit of existence is extended beyond the sensible world as well. A significant distinctive matter in this regard is the method by which the discussion is settled. The aim in this paper is to deal with the method by virtue of which the question about the limit of existence could be dealt with. The writers attempt to reveal that in Plato and Avicenna`s view the method of investigation into sensible being was a common feature. The result displays that both philosophers took the method of investigation into sensible world in action with different metaphysical implication. Plato reached to Ideas and the world of Forms while the Avicenna resulted in natural universal which shared its existence with particular things in sensible world.