Contiguity to home can never excite our ideas of home, unless we believe that it really exists.
 David Hume, An Enquiry Concerning Human Understanding (1748). copy citation

Context

“We may observe, that, in these phaenomena, the belief of the correlative object is always presupposed; without which the relation could have no effect. The influence of the picture supposes, that we believe our friend to have once existed. Contiguity to home can never excite our ideas of home, unless we believe that it really exists. Now I assert, that this belief, where it reaches beyond the memory or senses, is of a similar nature, and arises from similar causes, with the transition of thought and vivacity of conception here explained.” source