If Someone Buys a Piece of Artwork That Neither the Buyer

Question 158

If someone buys a piece of artwork that neither the buyer nor seller knows is a masterpiece,this is considered a mutual mistake of value.Can the seller rescind such a contract? If,however,a buyer and seller think the piece of artwork being sold is a particular masterpiece,but in fact it is not,this is considered a mutual mistake of fact.Can the buyer in this case rescind the contract? Why is the result different in these two situations? What is different about the two situations that would suggest that they have different outcomes?