Quotations from Hugh Everett, one of the original theorists of quantum mechanics

“It is not so much the system which is affected by an observation as the observer, who becomes correlated to the system.”

“Once we have granted that any physical theory is essentially only a model for the world of experience, we must renounce all hope of finding anything like “the correct theory.” There is nothing which prevents any number of quite distinct models from being in correspondence with experience (i.e., all “correct”), and furthermore no way of ever verifying that any model is completely correct, simply because the totality of all experience is never accessible to us.”