Murphy v. Arnsom is a United States Supreme Court case that was decided in 1877. The case involved a dispute between two parties over a contract for the sale of land. The plaintiff, Murphy, had entered into a contract with the defendant, Arnsom, to purchase a tract of land. The contract stated that the land was to be paid for in installments, with the final payment due in 1876. However, Arnsom refused to accept the final payment, claiming that the contract was void because it had not been properly executed. The Supreme Court held that the contract was valid and enforceable. The Court found that the contract was valid under the Statute of Frauds, which requires certain contracts to be in writing and signed by the parties in order to be enforceable. The Court also held that the contract was not void due to the fact that it had not been properly executed, as the parties had acted in good faith and had intended to be bound by the contract. The Court's decision in Murphy v. Arnsom established that contracts that are not properly executed can still be enforced if the parties acted in good faith and intended to be bound by the contract. This decision has been cited in numerous subsequent cases and is still used today to determine the enforceability of contracts.

Justice Field wrote the dissenting opinion in Murphy v. Arson, arguing that the majority's decision was inconsistent with prior Supreme Court decisions and would lead to a "confusion of titles" if allowed to stand. He argued that when an individual purchases land from another party, they are not required to inquire into any potential disputes over title or ownership; rather, it is assumed that the seller has good title and can convey it without issue. In this case, he noted that Mr. Murphy had purchased his property from a third party who had obtained their deed through legal means; thus there should be no dispute as to its validity or legality since all parties involved acted in good faith at every step of the transaction process. Furthermore, Justice Field argued that allowing Mrs. Arnson's claim would create a dangerous precedent whereby individuals could bring forth claims against others for lands which were legally acquired by them years after such acquisition occurred - something which could potentially cause great harm and confusion within society as whole due to its unpredictable nature