This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
If the parol evidence rule is a rule of substantive law and the evidence of prior or contemporaneous negotiations is inadmissible, and not because of any defect in the evidence itself, but because such negotiations are not a part of the contract, such objection is not waived by failure to object to such evidence as inadmissible when it is offered at the trial, since such evidence, even if it is received without objection, does not tend to prove the question at issue, which is the actual agreement entered into between the parties as embodied in the writing and the true meaning and effect thereof. Failure to object to such evidence when it is offered or before the issues of fact are decided by the trier of fact, does not operate as a waiver of such an objection to such evidence on the part of the party who would necessarily prevail if the written contract were regarded as the sole and exclusive repository of the intention of the parties, since there is a total failure of proof on the part of the adversary party and the legal effect of this total failure can not be waived by failure to object to such evidence when it is offered. On the other hand, if the parol evidence rule is a rule of evidence and not a rule of substantive law, and if the only objection to such evidence is that it is an improper means of proving a fact embodied in the issue, failure to object to such evidence when offered at the trial, or possibly failure to object to such evidence at any time before the issue of fact is determined by the trier of fact, operates as a waiver of an objection of this sort to such evidence, and the question can not be raised for the first time in the reviewing court. A few courts are consistent in applying the theory that the parol evidence rule is a rule of substantive law, and in holding accordingly that failure to object to such evidence does not alter the legal effect of a total failure of proof on the part of the party who contends that the terms of the real contract between the parties are different from those which appear in the writing.1 If there is no conflict in evidence as to the execution and contents of the written contract, and if a special verdict has been rendered to the effect that an inconsistent oral contract exists, a judgment should be rendered notwithstanding such special verdict.2
1 Dollar v. International Banking Corporation, 13 Cal. App. 331, 109 Pac. 499; Goddard v. Cutts, 11 Me. 440.
"Appellant presents a petition for a rehearing on this appeal wherein, among other things, exception is taken to the following language contained in the opinion of this court, filed April 28,1910, to wit: 'No objection was made to the introduction of this testimony, but the incompetency of parol evidence to vary a writing may be considered as a matter of law,' In support of the contention that this is not a correct declaration of the law a number of cases are cited to sustain the proposition that, in the absence of objection, secondary evidence is sufficient to support the findings of a court based thereon. The rule declared by this court is entirely distinct from that applied in those cases. Whether or not a contract in writing may be varied by parol evidence is a question of substantive law, while the admission or rejection of secondary evidence is governed by the rules of evidence. (.1 Greenleaf on Evidence, 16th ed., Sec. 305a.) Where a contract is reduced to writing, whether required by law to be written or not, the writing supersedes all other negotiations and stipulations concerning the matter made at the time or prior thereto. (Civ. Code, Sec. 1625.) If the terms as agreed upon have not all been reduced to writing, these can be supplied only by an appropriate proceeding, or under proper allegations. (Code Civ. Proc., Sec. 1856; Germain Fruit Co. v. Armsby Co., 153 Cal. 595 [96 Pac. 319].) By way of illustration of the distinction between the rule declared by this court and that cited by appellant, it may be said that parol or secondary evidence, unobjected to, might supply the terms, or purport, of a contract which had been reduced to writing, and, in this form, furnish sufficient proof to sustain a finding, but parol evidence would neither be admissible to vary this contract, nor, if admitted without objection, be sufficient to support a finding which was in conflict with or which in any manner varied the original written contract which the parties entered into. The purpose of the rule relating to the varying of a writing by parol evidence is to prohibit this from being done, while the rule relating to the admission of secondary evidence goes only to the form in which the evidence may be introduced. These rules are in no way inconsistent and the rule as to secondary evidence is not applicable here." Dollar v. International Banking Corporation, 13 Cal. App. 331. 109 Pac. 499.
It must be admitted, however, that the numerical weight of authority seems to regard the parol evidence rule from this standpoint as a rule of evidence and not a rule of substantive law, and to hold that failure to object to such evidence when offered at the trial or at least failure to move to strike it out before the case is finally submitted, operates as a waiver of such objection.3 If oral evidence of a warranty has been received without objection in the trial court, the reviewing court will not reverse, although the
"It does appear, from the testimony of the witnesses for the defendants, that the suits were withdrawn, a dis-charge on the copy of the old notes given, and the note in question signed and delivered, upon the condition that the original notes should be procured, and sent to the defendant, Cutts, within two weeks; and that to this the attorney of the plaintiffs assented. This is manifestly a condition subsequent, not to be found in the note, but attempted to be attached thereto by parol evidence. This testimony was received without objection; but when called upon to determine whether the verdict is or is not against the weight of evidence, it must be weighed, according to the rules established by law. This testimony, such as it is, is contradicted by two witnesses. If false, it sought not to affect the note; and if true, it was not competent to change its terms, or interpose new conditions. The defense itself is without merits." Goddard v. Cutts, 11 Me. 440.