(T)he making of a contract depends not on the agreement of two minds, in one intention, but on the agreement of two sets of external signs not on the parties' having meant the same thing but on their having said the same thing.

Holmes, The Path of the Law, in Collected Legal Papers 178, as quoted by Judge Friendly in Frigaliment Importing Co. v. B. N. S. International Sales Corp., 190 F. Supp. 116, 117 (S.D.N.Y.1960) (emphasis in original). See also Gilmore, The Death of Contract (1974).

The strongest external sign of agreement between contracting parties is the words they use in their written contract. Thus, the sanctity of the written words of the contract is embedded in the law of contract interpretation. As it has been variously put:

(A) court will make no inference or give any construction to the terms of a written contract that may be in conflict with the clearly expressed language of the written agreement.

National Cash Register Co. v. Modern Transfer Co., Inc., 224 Pa.Super. 138, 142, 302 A.2d 486, 488 (1973).A court is not authorized to construe a contract in such a way as to modify the plain meaning of its words, under the guise of interpretation.

Best v. Realty Management Corp., 174 Pa.Super. 326, 329-330, 101 A.2d 438, 440 (1953).

When a written contract is clear and unequivocal, its meaning must be determined by its contents alone.

East Crossroads Center, Inc. v. Mellon-Stuart Co., 416 Pa. 229, 230, 205 A.2d 865, 866 (1965).

The rule enunciated in Gianni v. Russell & Co., Inc., (281 Pa. 320, 126 A. 791) supra, is firmly embedded in the law of Pennsylvania and from that rule we will not permit a deviation for it is essential that the integrity of written contracts be maintained. . . . 'Where parties, without any fraud or mistake, have deliberately put their engagements in writing, the law declares the writing to be not only the best, but the only, evidence of their agreement: (citing cases). All preliminary negotiations, conversations and verbal agreements are merged in and superseded by the subsequent written contract * * * and unless fraud, accident or mistake be averred, the writing constitutes the agreement between the parties, and its terms cannot be added to nor subtracted from by parol evidence: (citing cases).'

United Refining Co. v. Jenkins, 410 Pa. 126, 134, 189 A.2d 574, 578 (1963) (emphasis and citations omitted).9

In a world where semantics is a science instead of an art we might be able to read a contract and understand it without question. However, English is often a difficult and elusive language, and certainly not uniform among all who use it. External indicia of the parties' intent other than written words are useful, and probably indispensable, in interpreting contract terms. If each judge simply applied his own linguistic background and experience to the words of a contract, contracting parties would live in a most uncertain environment. Therefore, under Pennsylvania law we are instructed that:

A court must be careful not to 'retire into that lawyers Paradise where all words have a fixed, precisely ascertained meaning; where men may express their purposes, not only with accuracy, but with fullness; and where, if the writer has been careful, a lawyer, having a document referred to him, may sit in his chair inspect the text, and answer all questions without raising his eyes.

In Re Estate of Breyer, 475 Pa. 108, 379 A.2d 1305, 1309 n.5 (1977) (citations omitted), quoting Thayer, Preliminary Treatise on Evidence 428, as quoted in 3 Corbin, Contracts § 535 n.16 (1960);

In the construction of any contract, certain principles must guide us: (a) if there is any doubt as to the meaning of a term of a contract, such term should 'receive a reasonable construction and one that will accord with the intention of the parties; and, in order to ascertain their intention, the court must look at the circumstances under which the (contract) was made'; (b) in construing a contract we seek to ascertain what the parties intended and, in so doing, we consider the circumstances, the situation of the parties, the objects they have in mind and the nature of the subject matter of the contract; (c) 'However broad may be the apparent terms of the agreement, it extends only to those things concerning which the parties intended to contract, and the subject-matter of their negotiations may affect the meaning of the words they employ, especially if, in connection with that subject-matter, the conventional interpretation would give an unreasonable or absurd result.'

United Refining Co. v. Jenkins, 410 Pa. 126, 137-38, 189 A.2d 574, 580 (1963) (citations omitted) (emphasis deleted).

Courts are left with the difficult issue of determining as a matter of law which category written contract terms fall into clear or ambiguous. United Refining Co. v. Jenkins, supra; O'Farrell v. Steel City Piping Co., --- Pa.Super. ---, 403 A.2d 1319 (1979).10 There is a point at which interpretation becomes alteration of the written contract. We must determine if the trial judge went beyond that point.11

Intellectual uncertainty; . . . the condition of admitting of two or more meanings, of being understood in more than one way, or referring to two or more things at the same time . . .

Webster's Third New International Dictionary (unabr.1971).

A court must have a reference point to determine if words may reasonably admit of different meanings. Under a "four corners" approach a judge sits in chambers and determines from his point of view whether the written words before him are ambiguous. An alternative approach is for the judge to hear the proffer of the parties and determine if there is objective indicia that, from the linguistic reference point of the parties, the terms of the contract are susceptible of differing meanings. We believe the latter to be the correct approach.

It is the role of the judge to consider the words of the contract, the alternative meaning suggested by counsel, and the nature of the objective evidence to be offered in support of that meaning. The trial judge must then determine if a full evidentiary hearing is warranted. If a reasonable alternative interpretation is suggested, even though it may be alien to the judge's linguistic experience, objective evidence in support of that interpretation should be considered by the fact finder.12 See Corbin, Contracts § 542.

An analysis of Pennsylvania cases demonstrates that this approach is in accord with practice in the Pennsylvania courts.13 Accordingly we conclude that it was proper for the court here to consider extrinsic evidence.

But our approach does not authorize a trial judge to demote the written word to a reduced status in contract interpretation. Although extrinsic evidence may be considered under proper circumstances, the parties remain bound by the appropriate objective definition of the words they use to express their intent. Generally parties will be held to definitions given to words in specialized commercial and trade areas in which they deal. Similarly, certain words attain binding definition as legal terms of art. See e. g. Brockett v. Carnes, slip. op. (Pa.Super.Ct.Dec. 19, 1979). Dates, numbers and the like generally cannot be varied. See e. g. O'Farrell v. Steel Piping Co., supra.14 For example, extrinsic evidence may be used to show that "Ten Dollars paid on January 5, 1980," meant ten Canadian dollars, but it would not be allowed to show the parties meant twenty dollars. Trade terms, legal terms of art, numbers, common words of accepted usage and terms of a similar nature should be interpreted in accord with their specialized or accepted usage unless such an interpretation would produce irrational results or the contract documents are internally inconsistent.15

We have concluded that the district court here exceeded the permissible boundary of interpretation. We believe its interpretation of insolvency was improperly restrictive. Commercial parties entered a Buy-Sell Agreement using a well defined commercial term and legal term of art "insolvent." The court rejected the test which we believe an attorney or commercial creditor would use to determine if the borrowers were insolvent in any other context, and instead substituted a test for insolvency which excluded certain liabilities of the borrowers. This variation of the written words used in the contract was not justified by the evidence received. When the district judge received Mellon's evidence it should have rejected it as insufficient to vary the meaning of a commercial term as well established as "insolvent." In this case the district court added a term which made the condition a nullity. It ruled that, although the solvency of the borrowers was a condition in the written contract, the fact that the borrowers' solvency was not significantly considered by Aetna in evaluating the take-out loan minimized or nullified this clause of the contract.

The condition that the borrowers not be insolvent was added by Aetna and retained in the contract over Mellon's protests. The fact that the insolvency of the borrowers was not significantly considered by Aetna in evaluating the take-out loan is immaterial given the expression of that concern in the written words of the contract. The fact that Aetna thought it bore some risk of default if the occupancy rate of the project fell too low was not sufficient to vary the normal commercial meaning of the word "insolvent." Of course Aetna bore some risk of default Aetna's funding obligation extended over a ten year period. There was no substantial evidence for Mellon's interpretation of the contract other than evidence tending to show that Aetna was not significantly concerned with the borrowers' solvency until they desired an "out" to excuse their obligation to purchase a loan which had become unsound. Fortunately for Aetna it retained that "out" in the Buy-Sell Agreement despite specific objections from Mellon. See Testimony of DeLuca, Record at 515a-518a. At best, Mellon's officers admitted that they knew the insolvency clause was adverse to Mellon's interests, but they didn't "really" know what it meant. Testimony of DeLuca, Record at 518a. Mellon's evidence was simply insufficient to vary the clear meaning of the commercial term "insolvent."

Our holding the parties to a generally accepted commercial interpretation of the word "insolvency" in no way produces an irrational result. Aetna was to undertake the risk of a decline in the real estate market for ten years after it purchased the construction loan. Mellon was at risk of construction not being completed on time and within cost. The issue is who bore the risk that the borrowers' financial reserves could not carry the project from the date of the Buy-Sell Agreement to the closing on the permanent financing i. e. who bore the risk of a decline in the Atlanta real estate market from July of 1974 to August of 1975. It is not irrational to place that risk on Mellon, nor is it irrational to place it on Aetna.16 Aetna inserted the insolvency clause in the commitment. Mellon demanded that the clause be excluded from the Buy-Sell Agreement. Aetna refused. When Mellon signed the agreement notwithstanding the inclusion of the clause, it became bound by the usual meaning of insolvency. This result is not irrational and therefore does not compel the alternative meaning of insolvency suggested by Mellon. Mellon cannot now insert an exception to the solvency condition. "Where one of two innocent persons must sustain a loss, the law will place that burden on the party that has agreed to sustain it." F. J. Busse, Inc. v. Department of General Services, --- Pa.Cmwlth. ---, ---, 408 A.2d 578, 580 (1979). See International Systems, Inc. v. Personnel Data Systems, slip. op. (Pa. Superior Ct., Jan. 18, 1980).

Accordingly, we conclude that in determining the insolvency of the borrowers the district court must include all the assets and liabilities of the borrowers in applying both generally accepted commercial tests for insolvency. The notion of insolvency is measured both by a balance sheet showing all assets and liabilities and the test of whether one can meet current debts as persons engaged in a trade normally do.17IV. THE LETTER OF AUGUST 15, 1975

We find it necessary to respond to Mellon's alternative argument that notwithstanding the presence of the insolvency clause in the contract, Aetna waived any defense based on this clause by its letter of August 15, 1975. We believe that the letter of August 15, 1975, and the borrowers' affidavits of solvency submitted in response to that letter do not establish a separate contract obligating Aetna to purchase the construction loan nor do they constitute a waiver of the condition that the borrowers not be insolvent at the time Aetna would otherwise become obligated to purchase the loan. We are unable to perceive how this letter could be construed as an offer by Aetna to waive any of Aetna's contractual rights under the insolvency clause. This very letter reasserted Aetna's rights under that clause, reminded the borrowers that their solvency was a required condition precedent to funding the permanent loan, and asked for "sworn statements" to assure Aetna that the condition was fulfilled. The letter never unequivocally stated that Aetna would fund the loan upon submission of the statements, but only that Aetna would "be in a position" to fund the loan. In the context of complex commercial dealings courts must be careful not to take single acts or isolated correspondence out of the context of the entire situation and construe them as separate contracts or waivers of important contract rights unless such an intent is explicitly and clearly expressed.

When Aetna requested affidavits they were asking for sworn truthful statements of the borrowers' solvency.18 If the borrowers were insolvent when they signed affidavits swearing that they were solvent, then the return of those affidavits did not consummate a contract since the act of acceptance was not in conformity with the offer. If the affidavits were signed truthfully, then the letter and affidavits merely evidence that the condition of solvency was satisfied.19 In reality, the letter of August 15 was an attempt by Aetna to determine if the insolvency condition was fulfilled.

In addition, the cover letter which was returned with the affidavits and signed by the borrowers' attorney can be said to have derogated the contents of the affidavits. An acceptance must be unequivocal to be valid. In Re ABC-Federal Oil and Burner Co., 182 F. Supp. 928 (E.D.Pa.1960), aff'd 290 F.2d 886 (3d Cir. 1961); Hedden v. Lupinsky, 405 Pa. 609, 176 A.2d 406 (1962).

The district court determined that the material adverse change clause was not a condition precedent to Aetna's obligation to buy the construction loan. First, the district court noted that paragraph four of the Buy-Sell Agreement contained an extensive list of conditions precedent to Aetna's obligations. The material adverse change clause was not in that paragraph. Normally this might be probative evidence that the material adverse change clause was not a condition precedent. However, the material adverse change clause was in a totally different document, which preceded the Buy-Sell Agreement. The material adverse change clause was contained in the Loan Application, which in turn became part of the Permanent Commitment, which as previously noted, became part of the Buy-Sell Agreement by incorporation. Therefore, the fact that such a clause was not in paragraph four of the Buy-Sell Agreement does not by itself support the district court's conclusion that the material adverse change clause was not a condition precedent to Aetna's obligation. The insolvency condition also was not in paragraph four, but in the Permanent Loan Commitment.

The district court also held that the insolvency clause was not a condition precedent to Aetna's obligation based on the language of the clause. The clause stated:

If the application is approved, we (the borrowers) agree to the following: . . . we (the borrowers) will furnish evidence satisfactory to you (Aetna) at the date of funding that there has been no material adverse change in our financial or other condition. . . .

Record at 29a.

The rule in Pennsylvania is that a condition precedent to an obligation must be expressed by clear language or it will be construed as a promise or covenant. Language not clearly written as a condition precedent is presumed not to be, unless the contrary clearly appears to be the intention of the parties. Britex Waste Co. v. Nathan Schwab and Sons, 139 Pa.Super. 474, 12 A.2d 473 (1940); Potts Mfg. Co. v. Loffredo, 96 Dauph. 413 (Ct. of Common Pleas), aff'd, 235 Pa.Super. 294, 340 A.2d 468 (1974); Sharp v. McKelvey, 57 Lanc.Rev. 377, exceptions dismissed, 57 Lanc.Rev. 391, aff'd 196 Pa.Super. 138, 172 A.2d 580 (1961). We hold that it was not error for the district court to construe the material adverse change clause as a promise of the borrowers, and as consideration for Aetna's promise and not a condition precedent to Aetna's obligation. It was also not error for the district judge to hold that this clause was fulfilled. Aetna required no more information than they received, and expressed no dissatisfaction with this information. Aetna added the insolvency/bankruptcy condition in the acceptance of the application which already contained the material adverse change clause. It is a rational interpretation to view the insolvency clause as addressing Aetna's concerns about the borrowers' financial condition because it viewed the material adverse change clause as insufficient to cover the same potential problems. The material adverse change clause was the procedural way Aetna was to receive information about the financial status of the borrowers. Unless the borrowers and Mellon were in substantial noncompliance with their obligations under the Buy-Sell Agreement/Permanent Loan Commitment, Aetna was limited to the insolvency condition as a ground for refusing to purchase the construction loan.

On remand the district court should place the burden of proof on Mellon to establish the condition precedent that the borrowers were not insolvent as of August 1, 1975. The district court should include the liabilities of the Kensington Square project in deciding whether or not the borrowers were then insolvent. Aetna's letter of August 15, 1975, and the response thereto do not constitute a valid waiver of the condition precedent nor do they create a separate contract obliging Aetna to purchase the construction loan.20

The judgment of the district court will be vacated and the cause remanded for proceedings consistent with the foregoing.