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Symbolic Logic: A Razor-Edged Tool for Drafting and Interpreting Legal Documents, 66 Yale Law Journal 833 (1957)


A large amount of the litigation based on written instruments-whether

statute, contract, will, conveyance or regulation--can be traced to the draftsman's

failure to convey his meaning clearly. Frequently, of course, certain

items may purposely be left ambiguous, but often the question in issue is due

to an inadvertent ambiguity that could have been avoided had the draftsman

clearly expressed what he intended to say. In this Article it is suggested that

a new approach to drafting, using certain elementary notions of symbolic logic,

can go a long way towards eliminating such inadvertent ambiguity. This new

approach makes available to draftsmen a technique that achieves some of the

clarity, precision and efficiency of analysis that symbolic logic provides. In

addition, it can be a valuable aid in moving towards a more comprehensive

and systematic method of interpretation,' as well as drafting.

This approach is a compromise between expression in ordinary prose and

expression in the mathematical notation of symbolic logic-enough like ordinary

prose to be understood easily by any careful reader, enough like symbolic

logic to achieve some of its important advantages. It represents an

effort to adapt some of the techniques of symbolic logic to make more systematic

what is now best described as the "art" of drafting.

The first section will explain six elementary logical connectives: implication,

conjunction, coimplication, exclusive disjunction, inclusive disjunction and

negation. In order to simplify this exposition, trivial examples will be used

for purposes of illustration. In the second section the proposed system will

be applied to actual legal problems of drafting, interpretation, simplification

and comparison.

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