It will be noticed that Acts of Legislation are generally prospective and not retrospective in their application. The doctrine of estoppel also illustrates the meaning intended to be conveyed.
169. Nemo praesumitur malus. No one is presumed to be bad.
(See Max. No. 145.)
* 170. Nemo tenetur ad impossibile. No one is bound to an impossibility.
If a man contracts to do anything which is physically impossible, such contract is not binding on him; but where the contract is to do a thing which, though possible at the time, subsequently becomes impossible, it is otherwise; also if the impossibility is one personal only to the contractor. (See Max. No. 139.)
171. Nemo tenetur seipsum prodere. No one is bound to betray himself; i.e., cannot be compelled to criminate himself.
A well recognised rule of evidence in all cases. (See Max. No. 3.)
172. Nihil tam conveniens est naturali aequitati, quam unumquodque dissolvi eo ligamine quo legatum est. Nothing is so consonant to natural equity, as that a thing may be dissolved by the same means which made it binding.
173. Non accipi debent verba in demonstrationem falsam quae competunt in limitationem veram. Words which admit of a true meaning ought not to be received in a false sense, or one inconsistent with the facts.
Thus, where there is a subject-matter which answers in every particular to a description contained in a will or deed, no part of the description can be rejected so as to make it include more.