 Assuming that complex objects are ontologically dependent on their proper parts, we now have an infinite regress of entities, each of which is ontologically dependent on the next. Such an infinite regress has been thought by some metaphysicians to be objectionable, leading them to reject the possibility of gunk. Leibniz, for example, argues that there cannot be only “beings by aggregation” (i.e., composite objects), because this would lead to an infinite regress, with each being by aggregation being made up of further beings by aggregation, and so on ad infinitum.