Definition
A Latin term meaning disposition, intention, or mental impulse — the state of mind or affection of the will that accompanies or motivates an act. In classical legal usage, affectus refers not to an outward act but to the inward tendency, purpose, or inclination behind it. The concept operates as a proxy for what modern law calls intent or mens rea: the mental element that gives legal significance to conduct.
The term appears most persistently in two legal contexts:
1. JUROR CHALLENGE (propter affectum): A challenge to a juror on account of suspected bias, partiality, or favor — that is, because the juror's affectus toward a party or cause disqualifies them from neutral service. This is one of the recognized grounds for a challenge for cause under classical common law procedure.
2. CRIMINAL AND TORTIOUS INTENT: The proposition that wrongful conduct is constituted or punished by the affectus of the actor, even where the intended effect does not fully materialize. The maxim affectus punitur licet non sequatur effectus — "the intention is punished although the intended result does not follow" — encodes this principle.
Common Confusion
Affectus is sometimes loosely equated with animus, another Latin term for intent or mental state. They are not identical. Animus tends to denote a specific, directed purpose (as in animus furandi, the intent to steal), while affectus refers more broadly to the general disposition or emotional orientation of the mind at the time of an act. Affectus can shade toward inclination or feeling; animus is typically more volitional and purposive. In practice, classical sources use them interchangeably in some passages, but careful research requires attending to context. Both are distinct from dolus (deceit or fraudulent intent) and culpa (negligence or fault), though all four operate within the broader architecture of mental fault in civil and common law.
Why It Matters in Research
Researchers working in pre-modern common law, civil law, or canon law sources will encounter affectus as a load-bearing term in discussions of criminal liability, tortious injury, and procedural competence. Three navigational points matter:
First, the propter affectum challenge is the primary procedural context in which affectus appears in English common law sources. Blackstone's treatment (3 Bl. Comm. 363) and Coke on Littleton (Co. Litt. 156) are the standard reference points, and the term will surface in early jury-trial materials, writs, and challenge pleadings under this heading. Researchers tracing the history of juror bias doctrine should treat propter affectum as the controlling search term in older sources, not modern equivalents like "bias" or "impartiality."
Second, the maxim affectus punitur licet non sequatur effectus has doctrinal reach into inchoate offenses — attempt, conspiracy, and solicitation. Where early authorities grapple with whether incomplete crimes are punishable, this maxim often appears as foundational warrant. It is cited in 9 Coke 55 and recurs in treatise literature on criminal law. Researchers should be alert to it as evidence of early common law engagement with the problem of incomplete harm.
Third, Bracton's use of affectus (as compiled in Burrill) connects the term directly to the Roman law of theft and iniuria, grounding English doctrine in Digest sources. Where research crosses between civil law and common law traditions — especially in property, tort, or criminal law before the 18th century — affectus serves as a bridge term and its appearance can signal borrowing from Roman or canon law frameworks.
Historical Dictionary Support
Black's (both editions) and Burrill agree on the core meaning: disposition, intention, mental impulse. Burrill adds the most texture by quoting Bracton and the Digest directly, illustrating how affectus functioned in both civilian and early English legal writing. The Digest citation (47.10.3.1) places it in the law of iniuria; the Bracton citation (fol. 52b) places it in theft — consistent with affectus as the mental condition that makes an act legally wrongful rather than merely harmful.
What the historical dictionaries do not do is distinguish affectus from closely related mental-state terms, nor do they trace the concept into modern doctrine. That silence is itself informative: affectus largely disappears from English-language legal writing as the common law developed its own indigenous vocabulary for intent (malice, knowledge, purpose, recklessness). By the 19th century, the term survives mainly in Latin maxims and historical commentary rather than operative legal argument.
Jurisdictional Note
Affectus is a term of Roman and classical common law provenance and does not appear as operative legal vocabulary in modern Anglo-American statutes or codes. It remains relevant in civil law jurisdictions insofar as those systems retain closer ties to Roman law terminology, and in canon law where Latin legal vocabulary has continuous currency.