One who entertains a doubt as to the existence, present or future, of a certain fact, cannot be said to believe in and rely upon that fact. If he acts with any doubt that the fact exists or will exist, he is consciously "taking a chance." And if it develops that his doubt was well founded, he cannot justly claim to be the victim of a mistake. It follows that if the fact doubted, but assumed to be true, was essential to the existence of a duty or the availability of a right, he cannot claim to have acted in misreliance on such right or duty. Thus, if A pays money to B on account of a bill for services rendered although suspecting that he has already paid it or doubting whether the services have actually been rendered, he assumes the risk that by reason of the previous payment or of the nonperformance of the service, he is under no duty to make the payment. So, if A contracts unconditionally to make certain improvements upon B's premises, though doubtful of his ability to obtain some of the materials required for such improvements, he assumes the risk that by reason of a failure to obtain such materials he will not acquire a contract right to compensation. In either case, if A's suspicion or doubt turns out to have been well founded, he is not entitled to restitution. B,it is true, has received something for nothing; but why should a court of law assist A to recover what he has consciously risked and lost ?

Atl. 598; Alton v. First Nat. Bank, 1892, 157 Mass. 341, 344; 32 N. E. 228; 18 L. R. A. 144; 34 Am. St. Rep. 285, ("A mistake as to a fact . . . would not warrant a recovery, when, as here, the fact was a matter equally open for the inquiry and judgment of both parties, and the defendant had a right to assume that the plaintiff relied wholly on his own means of information."); Advertiser, etc., Co. v. City of Detroit, 1880, 43 Mich. 116; 5 N. W. 72; Wheeler v. Hatheway, 1885, 58 Mich. 77; 24 N. W. 780 (cf. Pingree v. Mutual Ins. Co., 1895, 107 Mich. 156; 65 N. W. 6); Peterborough v. Lancaster, 1843, 14 N. H. 382, 389; Brummitt v. McGuire, 1890, 107 N. C. 351; 12 S. E. 191, 193, ("Nor, if the payment be made in ignorance or mistake of fact, can it be recovered back, where the means of knowledge or information is in reach of the party paying, and he is negligent in obtaining it."); First Nat. Bank v. Taylor, 1898, 122 N. C. 569; 29 S. E. 831; Stevens v. Head, 1837, 9 Vt. 174; 31 Am. Dec. 617; Simmons v. Looney, 1896, 41 W. Va. 738; 24 S. E. 677, 678-9.

This incompatibility of assumption of risk with misreliance has not always been detected.1 The question is most likely to be raised in cases of benefits conferred in part performance of a contract by one who fails to complete his performance. For a further discussion, therefore, the reader is referred to the chapters dealing with contracts unenforceable because of impossibility of performance (post, Sec. 112 et seq.), and contracts unenforceable because of the plaintiff's breach (post, Sec. 164 et. seq.).