When a family member dies a dispute can often arise about the proper meaning of a will or other testamentary writing left by the deceased. Indeed, that is one of the most common sources of dispute in executries.
Such disputes can be protracted and difficult. Beneficiaries are often all absolutely certain as to what the deceased really wanted to happen on their death. So, it's important to ensure that the will is well drafted and free from ambiguity. Professionally drafted testamentary documents have an advantage over contracts in that they are the expression of the wishes of one party and, for that reason, are usually capable of clearer expression. However, it can still be difficult for the drafter to properly express what are often complex wishes of the deceased, particularly where the deceased is seeking to divide an estate between a number of beneficiaries. Despite all of this, precious little is ever written about the proper approach to interpretation compared to the amount that is written about the interpretation of contracts.
The exercise is similar to that for contracts (see Ashtead Plant Power Ltd v Granton Central Developments Ltd  CSIH 2). The court will consider the natural and ordinary meaning of the words of the document in light of a number of factors. First, the overall purpose of the testamentary writing has to be considered. Secondly, the documentary context of the document is important - i.e. the disputed provision should not be read in isolation but rather read in a way which makes sense of the whole document. Thirdly, the facts known to or assumed by the parties at the time that the document is executed. Fourthly, while the court must ignore evidence of the testator's subjective intention, common sense will be relevant in the event of ambiguity. In other words, if faced with two possible meanings, the court is entitled to choose the one which makes more sense taking into account the scheme of the document as a whole. These tests are set out clearly by the Supreme Court in Marley v Rawlings  UKSC 2 and followed in Scotland by Fulton v Muir  CSOH 25.
It is important to bear in mind that, like contracts, the exercise is an objective one and, as Lord Neuberger explained in Marley, the court will "put itself in the testator's armchair" in order to understand what they meant. However, the interpretation of wills is not quite the same as the interpretation of contracts and care has to be taken when reading English authorities like Marley because the approach in Scotland and England to interpretation of wills is not the same. The Scottish courts, as with contracts, have always refused to consider extrinsic evidence of the testator's intention (as opposed to extrinsic evidence of context outlined above) as part of the interpretation exercise (Blair v Blair 1849 12 D 97). However, while in contractual matters, the English courts would also adopt a strictly objective approach, they have a more lenient approach to extrinsic evidence in relation to wills. Section 21 of the Administration of Justice Act 1982 (which is discussed in Marley) expressly permits extrinsic evidence of the testator's intentions. That presumably includes earlier drafts of wills and/or notes of the testator's intentions. In commercial law earlier drafts of a contract or negotiating notes of the parties would never be admissible as evidence in either jurisdiction (Chartbrook Limited v Persimmon Homes Ltd  AC 1011; Luminar Lava Ignite v Mama Group plc 2010 SC 310 and Paterson v Angelline (Scotland) Limited  CSIH 33).
So Scots and English law are not the same in this area. However, that is not as significant an issue in a personal private law context as it is in a commercial context, where greater alignment between the jurisdictions is almost always desirable. As Lord Hodge has explained speaking extrajudicially "…there is a strong imperative for Scotland, which has an open economy with both high levels of external trade and non-Scottish ownership of its substantial businesses, to have a commercial law that people outside Scotland can readily understand. There is much less pressure for the modest harmonisation with English or European norms in our non-commercial private law, such as the law of wills" ("The Rectification of Wills: Marley v Rawlings, the Edinburgh Tax Network and Trust Bar, 12 February 2015).
The objective nature of the approach, of course, makes it just as important as it is with contracts that wills are professionally drafted. Executors need to be able to understand clearly the wishes of the deceased with them being capable of reasonably quick and easy implementation. Of course, there is room for executors to take a view on ambiguous provisions. However, what is often overlooked about the position of executors is that they are very often themselves beneficiaries and it can be difficult to separate their personal from professional interests. They too can become convinced as to the deceased's wishes and a dispute can arise again. Where it does, the court can step in and the principles outlined above will be followed in order to properly understand what the testator intended.