A more appropriate way to deal with those who deny the existence of the extra-mental physical world, by arguing that it is possible for it to be all a dream, or a virtual illusion, or something similar.
Changing Relations
Suppose there was a change in the relation between two relata. Does this necessarily mean that both changed? Or is it only proof for the changing of at least one?
Relations are Abstract
The Mutakalimun understand relations to be abstract objects, existing in the mind of the one who thinks about two or more essences. This article demonstrates why they held this to be the case.
Necessity of Axioms
Proving that one must affirm axiomatic propositions that are true without needing to be proven, and axiomatic concepts that are understandable without needing to be defined.
Contingency of Existent Possible Essences
Proof that if a possible essence exists, then this necessarily means that this essence acquired its existence from that which is other than itself.
Keys to the Unseen 