They should be told:

“You testified, on the basis of what you knew, that he was an expert in medicine, valuation, estimating fruit yields, identification by physical signs, or similar matters, and that his opinion in these matters should be accepted rather than yours. If we gave precedence to your opinion over his in these questions, that would undermine your testimony and your knowledge that he knows more about these matters than you do. Your reporting this does not conflict with accepting his opinion rather than yours in these matters. You may be correct when you say, ‘He knows more than we do,’ yet mistaken when you say, ‘We know more than someone who knows more than we do concerning the questions he disputes with us, in which he is more knowledgeable than we are.’ Indeed, your error in this latter claim is more obvious.”

A person may know that someone else is more knowledgeable than he is about crafts such as farming, weaving, building, sewing, and others, without knowing the details of that craft himself. If he then disagrees with that more knowledgeable person, giving precedence to the latter’s opinion on the disputed matters does not undermine the grounds on which he recognized that person’s greater knowledge.

It is well known that the gulf between the Messenger, may Allah bless him and grant him peace, and those endowed with reason is far greater than the gulf separating experts in theoretical and practical disciplines and rational sciences based on independent inquiry—such as medicine, identification by physical signs, estimating fruit yields, and valuation—from other people. Some people can become as knowledgeable in those theoretical and practical disciplines as their experts. But someone whom Allah has not appointed as a messenger to mankind cannot attain the standing of someone whom Allah Most High has appointed as a messenger to mankind, for