Defendant appeals from a judgment for plaintiff in an action for damages for injury to property under an indemnity clause of a contract.
*36 In 1960 defendant entered into a contract with plaintiff to furnish the labor and equipment necessary to remove and replace the upper metal cover of plaintiff’s steam turbine. Defendant agreed to perform the work “at [its] own risk and expense” and to “indemnify” plaintiff “against all loss, damage, expense and liability resulting from . . . injury to property, arising out of or in any way connected with the performance of this contract.” Defendant also agreed to procure not less than $50,000 insurance to cover liability for injury to property. Plaintiff was to be an additional named insured, but the policy was to contain a cross-liability clause extending the coverage to plaintiff’s property.
During the work the cover fell and injured the exposed rotor of the turbine. Plaintiff brought this action to recover $25,144.51, the amount it subsequently spent on repairs. During the trial it dismissed a count based on negligence and thereafter secured judgment on the theory that the indemnity provision covered injury to all property regardless of ownership.
Defendant offered to prove by admissions of plaintiff’s agents, by defendant’s conduct under similar contracts entered into with plaintiff, and by other proof that in the indemnity clause the parties meant to cover injury to property of third parties only and not to plaintiff’s property. 1 Although the trial court observed that the language used was “the classic language for a third party indemnity provision” and that “one could very easily conclude that ... its whole intendment is to indemnify third parties,” it nevertheless held that the “plain language” of the agreement also required defendant to indemnify plaintiff for injuries to plaintiff’s property. Having determined that the contract had a plain meaning, the court refused to admit any extrinsic evidence that would contradict its interpretation.
When the court interprets a contract on this basis, it deter *37 mines the meaning of the instrument in accordance with the ". . . extrinsic evidence of the judge’s own linguistic education and experience.” (3 Corbin on Contracts (1960 ed.) [1964 Supp. §579, p. 225, fn. 56].) The exclusion of testimony that might contradict the linguistic background of the judge reflects a judicial belief in the possibility of perfect verbal expression. (9 Wigmore on Evidence (3d ed. 1940) § 2461, p. 187.) This belief is a remnant of a primitive faith in the inherent potency 2 and inherent meaning of words. 3
The test of admissibility of extrinsic evidence to explain the meaning of a written instrument is not whether it appears to the court to be plain and unambiguous on its face, but whether the offered evidence is relevant to prove a meaning to which the language of the instrument is reasonably susceptible.
(Continental Baking Co.
v.
Katz
(1968)
A rule that would limit the determination of the meaning of a written instrument to its four-corners merely because it seems to the court to be clear and unambiguous, would either deny the relevance of the intention of the parties or presuppose a degree of verbal precision and stability our language has not attained.
*38 Some courts have expressed the opinion that contractual obligations are created by the mere use of certain words, whether or not there was any intention to incur such obligations. 4 Under this view, contractual obligations flow, not from the intention of the parties but from the fact that they used certain magic words. Evidence of the parties ’ intention therefore becomes irrelevant.
In this state, however, the intention of the parties as expressed in the contract is the source of contractual rights and duties. 5 A court must ascertain and give effect to this intention by determining what the parties meant by the words they used. Accordingly, the exclusion of relevant, extrinsic, evidence to explain the meaning of a written instrument could be justified only if it were feasible to determine the meaning the parties gave to the words from the instrument alone.
If words had absolute and constant referents, it might be possible to discover contractual intention in the words themselves and in the manner in which they were arranged. Words, however, do not have absolute and constant referents.- “A word is a symbol of thought but has no arbitrary and fixed meaning like a symbol of algebra or chemistry, . . .”
(Pearson
v.
State Social Welfare Board
(1960)
Although extrinsic evidence is not admissible to add to, detract from, or vary the terms of a written contract, these terms must first be determined before it can be decided whether or not extrinsic evidence is being offered for a prohibited purpose. The fact that the terms of an instrument appear clear to a judge does not preclude the possibility that the parties chose the language of the instrument to express different terms. That possibility is not limited to contracts whose terms have acquired a particular meaning by trade usage, 6 but exists whenever the parties’ understanding of the words used may have differed from the judge’s understanding.
Accordingly, rational interpretation requires at least a preliminary consideration of all credible evidence offered to
*40
prove the intention of the parties.
7
(Civ. Code, §1647; Code Civ. Proc., § 1860; see also 9 Wigmore on Evidence,
op. cit. supra,
§2470, fn. 11, p. 227.) Such evidence includes testimony as to the “circumstances surrounding the making of the agreement . . . including the object, nature and subject matter of the writing . . .” so that the court can “place itself in the same situation in which the parties found themselves at the time of contracting. ’’
(Universal Sales Corp.
v.
California Press Mfg. Co., supra,
In the present ease the court erroneously refused to consider extrinsic evidence offered to show that the indemnity clause in the contract was not intended to cover injuries to plaintiff’s property. Although that evidence was not necessary to show that the indemnity clause was reasonably susceptible of the meaning contended for by defendant, it was nevertheless relevant and admissible on that issue. Moreover, since that clause was reasonably susceptible of that meaning, *41 the offered evidence was also admissible to prove that the clause had that meaning and did not cover injuries to plaintiff’s property. 9 Accordingly, the judgment must be reversed.
Two questions remain that may arise on retrial. On the theory that the indemnity clause covered plaintiff’s property, the trial court instructed the jury that plaintiff was entitled to recover unless all of “. . . the following conditions [were found] to exist:
“1. That Pacific Gas and Electric Company continued to *42 maintain independent operation, on the premises whereon the installation of the cover was in progress;
“2. That the damage to the turbine was unrelated to the Defendant G. W. Thomas Drayage & Rigging Company, Inc. ’s performance;
“3. That the plaintiff was guilty of active, affirmative negligence ; and
“4. That such active negligence related to a matter over which the plaintiff exercised exclusive control. ”
The instruction was based on certain guidelines discussed in
Goldman
v.
Ecco-Phoenix Elec. Corp.
(1964)
To prove the amount of damages sustained, plaintiff presented invoices received from Ingersoll-Rand, the manufacturer and repairer of the turbine, the drafts by which plaintiff had remitted payment, and testimony that payment had been made. Defendant objected to the introduction of the invoices on the ground that they were hearsay. Subsequently, plaintiff called a mechanical engineer who qualified as an expert witness on the repair of turbines. On the basis of photographs of the damage after the accident, he testified that to repair the turbine it was reasonable and necessary to dismantle it completely, magnafiux all parts, replace all blades in wheels that had been damaged, reassemble the rotor, balance it, “indicate” it and centrifugate it. Similar repairs were listed in the invoices, and over objection the witness was allowed to testify that the amounts charged therefor were reasonable.
Since invoices, bills, and receipts for repairs are hearsay, they are inadmissible independently to prove that liability for the repairs was incurred, that payment was made, or
*43
that the charges were reasonable.
(Plonley
v.
Reser
(1960)
The individual items on the invoices, however, were read, not to corroborate payment or the reasonableness of the charges, but to prove that these specific repairs had actually been made. No qualified witness was called to testify that the invoices accurately recorded the work done by Tngersoll-Rand, and there was no other evidence as to what repairs were made. This use of the invoices was error.
(California Steel Buildings, Inc.
v.
Transport Indemnity Co.
(1966)
Since plaintiff’s expert’s testimony as to the reasonableness of the charges was based on hearsay evidence inadmissible to prove that the repairs had been made, defend
*44
ant’s objections to it should have been sustained. “ [A]n expert must base his opinion either on facts personally observed or on hypotheses that find support in the evidence. ’ ’
(George
v.
Bekins Van & Storage Co.
(1949)
The judgment is reversed.
Peters, J., Mosk, J., Burke, J., Sullivan, J., and Peek, J., * concurred.
McComb, J., dissented.
Notes
Although this offer o£ proof might ordinarily be regarded as too general to provide a ground for appeal (Evid. Code, § 354, subd. (a);
Beneficial etc. Ins. Co.
v.
Kurt Hitke
&
Co.
(1956)
E.g., “The elaborate system of taboo and verbal prohibitions in primitive groups; the ancient Egyptian myth of Khern, the apotheosis of the words, and of Thoth, the Scribe of Truth, the Giver of Words and Script, the Master of Incantations; the avoidance of the name of God in Brahmanism, Judaism and Islam; totemistie and protective names in mediaeval Turkish and Finno-Ugrian languages; the misplaced verbal scruples of the ‘ Précieuses ’; the Swedish peasant custom of curing sick cattle smitten by witchcraft, by making them swaEow a page torn out of the psalter and put in dough. . . .’ from Ullman, The Principles of Semantics (1963 ed.) 43. (See also Ogden and Richards, The Meaning of Meaning (rev. ed. 1956) pp. 24-47.)
“ ‘Rerum enim vocabula immutabilia sunt, homines mutabilia,’ ” (Words are unchangeable, men changeable) from Dig. XXXIII, 10, 7, § 2, de sup. leg. as quoted in 9 Wigmore on Evidence, op. cit. supra, $ 2461, p. 187.
”A contract has, strictly speaking, nothing to do with the personal, or individual, intent of the parties. A contract is an obligation attached by the mere force of law to certain acts of the parties, usually words, which ordinarily accompany and represent a known intent. ’
’ (Hotchkiss
v.
National City Bank of New York
(S.D.N.Y. 1911)
”A contract must be so interpreted as to give effect to the mutual intention of the parties as it existed at the time of contracting, so far as the same is ascertainable and lawful.” (Civ. Code, § 1636; see also Code Civ. Proc., § 1859;
Universal Sales Corp.
v.
California Press Mfg. Co.
(1942)
Extrinsic evidence of trade usage or custom has been admitted to show that the term ‘ ‘ United Kingdom ” in a motion picture distribution contract included Ireland
(Ermolieff
v.
R.K.O. Radio Pictures, Inc.
(1942)
When objection is made to any particular item of evidence offered to prove the intention of the parties, the trial court may not yet be in a position to determine whether in the light of all of the offered evidence, the item objected to will turn out to be admissible as tending to prove a meaning of which the language of the instrument is reasonably susceptible or inadmissible as tending to prove a meaning of which the language is not reasonably susceptible. In such case the court may admit the evidence conditionally by either reserving its ruling on the objection or by admitting the evidence subject to a motion to strike. (See Evid. Code, § 403.)
Extrinsic evidence has often been admitted in such cases on the stated ground that the contract was ambiguous (e.g.,
Universal Sales Corp.
v.
California Press Mfg. Co., supra,
The court’s exclusion of extrinsic evidence in this case would be error even under a rule that excluded such evidence when the instrument appeared to the court to be clear and unambiguous on its face. The controversy centers on the meaning of the word “indemnify” and the phrase “all loss, damage, expense and liability.’’ The trial court’s recognition of the language as typical of a third party indemnity clause and the double sense in which the word ‘ ‘ indemnify ’ ’ is used in statutes and defined in dictionaries demonstrate the existence of an ambiguity. (Compare Civ. Code, § 2772, “Indemnity is a contract by which one engages to save another from a legal consequence of the conduct of one of the parties, or of some other person, ’ ’ with Civ. Code, § 2527, “ Insurance is a contract whereby one undertakes to indemnify another against loss, damage, or liability, arising from an unknown or contingent event.” Black’s Law Dictionary (4th ed. 1951) defines “indemnity” as “A collateral contract or assurance, by which one person engages to secure another against an anticipated loss or to prevent him from being damnified by the legal consequences of an act or forbearance on the part of one of the parties or of some third person.” Stroud’s Judicial Dictionary (2d ed. 1903) defines it as a “Contract ... to indemnify against a liability. ...” One of the definitions given to ‘ ‘ indemnify ’ ’ by Webster’s Third New International Diet. (1961 ed.) is “to exempt from incurred liabilities. ’ ’)
Plaintiff’s assertion that the use of the word “all” to modify “loss, damage, expense and liability” dictates an all inclusive interpretation is not persuasive. If the word “indemnify” encompasses only third-party claims, the word “all” simply refers to all such claims. The use of the words “loss,” “damage,” and “expense” in addition to the word “liability” is likewise inconclusive. These words do not imply an agreement to reimburse for injury to an indemnitee’s property since they are commonly inserted in third-party indemnity clauses, to enable an indemnitee who settles a claim to recover from his indemnitor without proving his liability.
(Carpenter Paper Co.
v.
Kellogg
(1952)
The provision that defendant perform the work ‘ ‘ at Ms own risk and expense ’ ’ and the provisions relating to insurance are equally inconclusive. By agreeing to work at its own risk defendant may have released plaintiff from liability for any injuries to defendant’s property arising out of the contract’s performance, but this provision did not necessarily make defendant an insurer against injuries to plaintiff’s property. Defendant’s agreement to procure liability insurance to cover damages to plaintiff’s property does not indicate whether the insurance was to cover all injuries or only injuries caused by defendant’s" negligence.
It might come in under the business records exception (Evid. Code, §1271) if “. . . supported by the testimony of a witness qualified to testify as to its identity and the mode of its preparation.”
(California Steel Buildings, Inc.
v.
Transport Indemnity Co., supra,
Retired Associate Justice of the Supreme Court gittÍPg Wider assign» meat by the Chairman of the Judicial Council.
