First Principles of Business Law

6.13. Example of 'expressio unius' and 'ex abundanti cautela'

Consider each of the phrases below, one at a time. You have to decide how to interpret each separate phrase.

To properly interpret each phrase, you must first decide whether to apply EITHER the 'expressio unius' principle, OR the 'ex abundanti cautela' principle. This will depend on which of these principles seems most appropriate to each phrase. By correctly applying the appropriate principle you can decide how best to interpret that phrase.

1. 'chickens and ducks' should be interpreted to mean any domestic poultry, including chickens and ducks.

2. 'chickens, ducks and domestic poultry' should be interpreted to mean any domestic poultry, including chickens and ducks.