Neuro-Nonsense

Neuroscientists can bring it about that a patient experience certain visions — say, of a chair — either by stimulating the relevant neural pathways, or by way of psychoactive drugs. Of course, this does nothing to persuade us that chairs are therefore reducible to the electro-chemical activity in our brains; or, put differently, that they lack extra-mental existence. This being the case, why think that an artificially-induced religious experience in any way implies the non-existence of the object of such an experience?