omission

Omission is the act of leaving something out, whether deliberately or inadvertently. It stands in contrast to commission, the act of including or doing something. The term is used across disciplines—linguistics, philosophy, law, medicine, journalism, and ethics—to describe situations where information, actions, or components are not included. Etymologically, omission derives from the Latin omittere, meaning to send away, neglect, or leave out. In practice, omissions can influence meaning, accountability, and outcomes by limiting disclosure or altering interpretation.

In linguistics, omission refers to ellipsis—the omission of words recoverable from context. In rhetoric and argumentation, it can function as a device or as a flaw. The fallacy of omission, often called the fallacy of the missing premise, occurs when crucial information is left unstated and the conclusion appears justified on incomplete grounds. Omission can also bias communication through selective reporting or cherry-picking data.

Legally and ethically, omissions matter when there is a duty to disclose. In contract, fiduciary, or criminal contexts, failing to reveal relevant information can create liability or criminal exposure. Ethically, withholding information may violate informed consent, patient autonomy, professional obligations, or public trust, though there are circumstances where non-disclosure is legally permissible or necessary for privacy, safety, or confidentiality. In medicine, clinicians balance beneficence with respect for the patient’s right to know.

Across fields, consideration of omissions supports transparency and accountability. Recognizing missing information helps prevent misinterpretation, bias, or unfair outcomes. Standards, disclosure requirements, and methodological safeguards aim to minimize harmful omissions and to document reasons for withholding information, allowing readers, patients, or judges to assess what is known, what is not, and why.