The earliest simple contracts recognized by the law were unilateral. The first recognition of bilateral contracts seems to have been about the end of the sixteenth century.30

When endeavoring to apply the doctrine of consideration to bilateral contracts a lawyer instinctively seeks to apply the same definition that has been adopted for unilateral contracts. Let it be supposed that this is detriment to the promisee or perhaps, as an alternative, benefit to the promisor. Such detriment or benefit may be sought in bilateral agreements either in the making of a promise in fact, or in the obligation in law created by a promise. Professor Ames took the former alternative;31 Sir Frederick Pollock,32 though saying, "It is true that the promise itself, not the obligation thereby created is the consideration," has inserted in the last edition of his treatise a passage which seems inconsistently to imply that not the promise in fact, but the obligation of the promise is requested; 33 and at all events is explicit that whether or cents." Pollock (8th Eng. ed.), 191. No doubt even if merely a. promise in fact is asked for, the request contem-plates, not the utterance of the words as a meaningless formula, but as a manifestation, of the speaker's intent. Possibly this is all the learned author

29 In Wichita Mill & Elevator Co. v. Liberal Elevator Co., 243 Fed. 99, 102, 155 C. C. A. 629, the court held that a seller's delay in shipping goods, though requested as consideration, created no contract, "for such delay was caused by its absolute inability to ship and not by its compliance with the buyer's request."

30 Strangborough v. Warner, 4 Leonard, 3 (1589); Gower v. Capper, Cro. Elia. 543 (1597); Nichols v. Rayn-bred, Hob. 88 (1615). In Pecke v. Redman, Dyer, 113 (1555), the parties bad entered into a bilateral agreement for the sale of grain in installments.

The defendant failed to pay for installments furnished, and the judges were evenly divided in opinion as to the plaintiff's right to recover for future profit as well as for the non-payment for what had already been delivered.

31 12 Harv. L. Rev. 29, 32.

32Principles of Contract, 8th Eng. ed., 192, 3d Am. ed., 202.

33 "If it be suggested that the mere utterance of words of promise is trouble enough to be a consideration, the answer is that such is not the nature of the business. Moving of the lips to speak or of the fingers to write is not what the promisor offers or the promisee ac~ not the making of the promise as a fact or the obligation of the promise in law is requested, the reason that a promise is sufficient consideration is because it creates a detrimental obligation. Professor Langdell also 34 is explicit only to the same extent. He Bays that the making of a "binding promise" is something of value; and in his argument,35 applies his test for consideration-detriment to the promisee-to the obligation assumed to be created by the promise.36

It seems probable that generally speaking, it is the promise in fact which the offeror requests-not a legal obligation. This is shown, as Professor Ames has said, by the form which such an offer ordinarily takes in fact, and by the form in which a bilateral contract is declared upon, the plaintiff stating merely that in consideration of his promise, the defendant promised. An offeror contemplating the formation of a bilateral contract says nothing of obligations, and asks only a promise in fact. Whether the offeror has bound himself by an obligation and whether he has got one in return is for the law to decide. This is true generally in the formation of contracts.37 If it were true that the request of the offeror were for an obligation rather than for a promise in fact, no fair construction of the offer could permit any other conclusion than that the obligation requested by the offeror was an effective and enforceable obligation, not one unenforceable or voidable at the option of the promisor. Yet, promises which are voidable or unenforceable on account of fraud, infancy, the Statute of Frauds, or illegality, are sufficient to support counter-promises.38 If the counter-promisor in such a bargain requested a legal obligation, it can hardly be true that he has received what he asked for. Certainly no offeror who in terms requested an obligation could have had in mind such a feeble bond.

34Summary of Contracts, Sec. 81.

35 E, g., Summary of Contracts, J 84.

36 Professor Ashley, who follows Langdell closely, argues that "in the average case" it is the obligation not merely the promise in fact which the offer for a bilateral contract requests. Law of Contracts, Sec. 31.

37 See supra, Sec. 21.

38See infra, Sec.105.

It will not do to urge that a voidable or unenforceable obligation is recognized by the law as within the pale of legal obligations. The inquiry here concerns what the offeror in fact requests and the law cannot, under recognized rules, impose a contract upon him unless he has been given what his request reasonably should be understood to mean. Contracts where one promise is voidable or unenforceable present some difficulty with regard to the law of consideration,39 but it has not been supposed that they violate fundamental principles of mutual assent.

It is doubtless generally true, though not always, that the reason why the offeror requests a promise in fact is because he expects thereby to acquire an obligation in law, but the reason for his request must not be confused with the request itself.

It must be admitted, however, that it is possible for an offeror to request in his offer the creation of a legal obligation. A can certainly say to B,-"If you will give me a simple contract right against you for your horse, I will give you a simple contract right against me for one hundred dollars," and it will probably not be doubted that acceptance of such an offer will create a contract, or that the validity of an agreement which provided in terms for the exchange of legal obligations, barring perhaps cases of voidable and of unenforceable promises, will be tested in the same way as if the offeror had requested a promise in fact rather than an obligation in law. So that even if ordinarily it is merely a promise in fact for which the offeror asks, as it is at least possible that an obligation in law may be requested, any difficulties which are involved in that assumption must be met. A technical difficulty, at least, in applying to bilateral contracts the test of consideration applicable to unilateral contracts exists either on the assumption that a promise in fact is requested or on the assumption that an obligation in law is desired.

If it is the promise in fact which the offeror requests, the inquiry naturally follows, why does not a bilateral contract arise whenever a requested promise is given in response to an offer? No satisfactory answer to this question can be made if the definition of consideration in unilateral contracts is of universal application, for whichever of various definitions that have been suggested as appropriate for unilateral contracts is adopted, the act of making a promise at request will technically satisfy its requirements.

39See infra, Sec.105.

On the other hand, if the offeror were conceived of as asking for a legal obligation, the opposite difficulty is presented in any attempt to apply to bilateral agreements the definition of consideration appropriate to unilateral contracts. The inquiry has been made by Sir Frederick Pollock, "What logical justification is there for holding mutual promises good consideration for each other? None, it is submitted." 40 And this conclusion is justified, if the only principles which we have to go upon are that the offeror requests a legal obligation as the return for his offer, and that in that legal obligation must be found a detriment or benefit necessary under the definition of consideration in unilateral contracts. For these premises involve inevitably a circular line of argument. If a detriment is necessary to support a promise, and therefore to give rise to an obligation binding upon either party, there can be no detriment without an obligation, and, under the rule of consideration which it is sought to apply, there can be no obligation without a detriment. Moreover, the burden is on one who asserts there is a contract to establish it. He will never be able to establish a bilateral contract upon these premises.41

4028 Law Quarterly Rev. 101; Pollock on Contracts, 8th Eng. ed., 191

41 It is at this point that the argument of Professor Langdell, in his essay on consideration, in 14 Harv. L. Rev. 496, fails. On page 601, he states the method of pleading in contracts, and says that by alleging and proving mutual promisee "the plaintiff will, in the absence of any proof by the defendant, establish his case unless the court shall be of opinion that one of the mutual promises, even if supported by a sufficient consideration, is not binding." But the cases of pleading suggested are not in point. It is, of course, true that a defendant who seeks to show that the facte stated in the declaration are not the only essential ones in the case, must allege and prove the additional facts; but when all the facte are before the court, the burden is always on the plaintiff to establish a legal cause of action. The question is not here in regard to disputed facts; all the facta must be taken as known. Under such circumstances the plaintiff has no right to assume that he has a cause of action in order to argue that he has one, nor can the court make any such assumption. When Professor