Meinong differentiated three levels of being: existence, subsistence and Aussersein or 'being-beyond-existence-andnon-existenclf. Concrete individuals, e.g. the stones, trees and men to be found today on the planet Earth, exist; abstract objects and states of affairs, e.g. the number three and thattoday-is-not-Sunday, subsist; and impossible objects and other oddities belong to the third level of being.