No force of imagination can convert us into another person, and make us fancy, that we, being that person, reap benefit from those valuable qualities, which belong to him.
 David Hume, An Enquiry Concerning the Principles of Morals (1751). copy citation

Context

“Now as these advantages are enjoyed by the person possessed of the character, it can never be SELF-LOVE which renders the prospect of them agreeable to us, the spectators, and prompts our esteem and approbation. No force of imagination can convert us into another person, and make us fancy, that we, being that person, reap benefit from those valuable qualities, which belong to him. Or if it did, no celerity of imagination could immediately transport us back, into ourselves, and make us love and esteem the person, as different from us. Views and sentiments, so opposite to known truth and to each other, could never have place, at the same time, in the same person.” source