(a) A court should take into account the essence and attributes of the document being examined. The court's treatment of extrinsic evidence at various stages of the analytical process may differ depending on the nature of the document. In general, the court ought to be more reluctant to allow extrinsic evidence to affect standard form contracts and commercial documents.
(b) If the court is satisfied that the parties intended to embody their entire agreement in a written contract, no extrinsic evidence is admissible to contradict, vary, add to, or subtract from its terms (see ss 93-94 of the Evidence Act). In determining whether the parties so intended, our courts may look at extrinsic evidence and apply the normal objective test, subject to a rebuttable presumption that a contract which is complete on its face was intended to contain all the terms of the parties' agreement. In other words, where a contract is complete on its face, the language of the contract constitutes prima facie proof of the parties' intentions.
(c) Extrinsic evidence is admissible under proviso ( f ) to s 94 to aid in the interpretation of the written words. Our courts now adopt, via this proviso, the modern contextual approach to interpretation, in line with the developments in England in this area of the law to date. Crucially, ambiguity is not a prerequisite for the admissibility of extrinsic evidence under proviso ( f ) to s 94.
(d) The extrinsic evidence in question is admissible so long as it is relevant, reasonably available to all the contracting parties and relates to a clear or obvious context. However, the principle of objectively ascertaining contractual intention(s) remains paramount. Thus, the extrinsic evidence must always go towards proof of what the parties, from an objective viewpoint, ultimately agreed upon. Further, where extrinsic evidence in the form of prior negotiations and subsequent conduct is concerned, we find the views expressed in McMeel's article and Nicholls' article persuasive. For this reason, there should be no absolute or rigid prohibition against evidence of previous negotiations or subsequent conduct, although, in the normal case, such evidence is likely to be inadmissible for non-compliance with the requirements set out at [125] and [128]-[129] above. (We should add that the relevance of subsequent conduct remains a controversial and evolving topic that will require more extensive scrutiny by this court at a more appropriate juncture.) Declarations of subjective intent remain inadmissible except for the purpose of giving meaning to terms which have been determined to be latently ambiguous.
(e) In some cases, the extrinsic evidence in question leads to possible alternative interpretations of the written words (i.e., the court determines that latent ambiguity exists). A court may give effect to these alternative interpretations, always bearing in mind s 94 of the Evidence Act. In arriving at the ultimate interpretation of the words to be construed, the court may take into account subjective declarations of intent. Furthermore, the normal canons of interpretation apply in conjunction with the relevant provisions of the Evidence Act, i.e., ss 95-100.
(f) A court should always be careful to ensure that extrinsic evidence is used to explain and illuminate the written words, and not to contradict or vary them. Where the court concludes that the parties have used the wrong words, rectification may be a more appropriate remedy.