Ignorance

Ignorance of the law does not excuse.

Ignorantia juris non excusat.

Source: 4 Bouv. Inst. no. 3828; 1 Story, Eq. Jur. s. 111; 2 Co. 36; 4 Bl. Comm. 27; Broom, Max. 253

Every man is presumed to know the law. This presumption is necessary to the functioning of any legal system — without it, the most brazen violator would have the readiest defense.

Ignorance of the law excuses no one, for all are presumed to know the law.

Ignorantia legis neminem excusat; omnes enim praesumuntur legem scire.

Source: 1 Co. 177; Broom, Max. 253; Rankin v. Mortimere, 7 Watts (Pa.) 374

The presumption of legal knowledge is universal and cannot be rebutted by a claim of personal unfamiliarity with the law.

Ignorance of fact excuses.

Ignorantia facti excusat.

Source: 2 Co. 3b; 2 Kent, Comm. 491; Code 1, 18, 10; Broom, Max. 253; Weisman, 57c; Weisman, 57d

Acts done and contracts made under a material mistake of fact are voidable. The distinction between ignorance of law (no excuse) and ignorance of fact (grounds for relief) is fundamental.

Ignorance of those things which one is bound to know does not excuse.

Ignorantia eorum quae quis scire tenetur non excusat.

Source: Hale, P.C. 42; Broom, Max. 267; 4 Bl. Comm. 27; Weisman, 57a

Where a duty to know exists — as with an officer of the court or a fiduciary — ignorance is treated as negligence, not as innocence.

The law aids the ignorant.

Lex succurrit ignoranti.

Source: Jenk. Cent. 15; Weisman, 44i; Weisman, 57h

Equity steps in where strict law would punish a party who acted in genuine ignorance of a material fact — particularly where the other party possessed superior knowledge.

Surplusage hurts not.

Surplusagium non nocet.

Source: 9 H. 6, 26; Jackson

Unnecessary or redundant matter in a pleading or instrument does not vitiate what is otherwise sufficient — superfluous words are disregarded rather than treated as fatal defects.