Definition
In legal contexts, "can" functions primarily as an auxiliary verb of capacity or permission rather than as a defined legal term. Its legal significance arises most often in the interpretation of contracts, statutes, and promises, where courts must determine whether "can" signals ability, permission, or obligation.
Where "can" appears in a promise or contractual undertaking — as in "I will pay as soon as I can" — courts have historically read it as an immediate or near-immediate obligation, not an indefinite deferral. The classic formulation: a promise to pay as soon as the debtor possibly can is, in contemplation of law, a promise to pay presently, because the law presumes every person able to pay their debts.
Common Language
Modern common usage (Wiktionary): "Can" functions as an expression of approval or reassurance — "OK, sure; indicates approval or acknowledgment."
Historical common usage (Webster's 1913): Identified as an obsolete form of "began," the past tense of "begin," occasionally found in old poetry.
Neither common usage aligns with the legal interpretive problem "can" creates. In legal instruments, "can" sits uneasily between permission (may) and ability (is able to), and the choice between those readings has determined the enforceability and timing of obligations. The gap between casual reassurance and legal capacity is where disputes arise.
Common Confusion
"Can" vs. "may": In formal legal drafting, "may" traditionally signals permission and "can" signals physical or legal capacity. In practice, courts frequently treat them as interchangeable in instruments where the drafter's intent is clear from context. Researchers working with older statutes or contracts should not assume this distinction was consistently observed. Modern legislative drafting guides increasingly treat "may" as the exclusive term of permission and discourage "can" in operative provisions precisely because of this ambiguity.
"Can" vs. "shall" or "must": When "can" appears in statutes or contracts alongside mandatory language, courts sometimes read it as directory rather than mandatory. This distinction matters in administrative law and regulatory interpretation.
Why It Matters in Research
The legal weight of "can" is almost entirely a problem of interpretive context, not definition. Researchers will encounter this term in three distinct situations:
First, in contract disputes over conditional promises. The common law rule — that "as soon as I can" means now — reflects a judicial presumption against self-imposed deferrals. This presumption appears in early nineteenth-century American case law and is the entry's most durable legal proposition. Researchers should treat it as a rule of construction, not a substantive definition.
Second, in statutory interpretation. Modern administrative and regulatory texts sometimes use "can" where "may" or "shall" would be more precise. Courts interpreting agency authority, individual rights, or procedural requirements have had to determine whether "can" confers discretion or describes capacity. The Anderson cross-reference to CASE (definition 4) suggests "can" was treated as analytically connected to the capacity to bring a legal action — a now-archaic usage worth noting when reading nineteenth-century procedural texts.
Third, in the regulatory context: CAN as acronym. The federal CAN-SPAM Act (Controlling the Assault of Non-Solicited Pornography And Marketing Act) uses "CAN" as part of a constructed acronym. Researchers searching Law Mind's corpus for "CAN" in commercial law or consumer protection contexts will surface materials related to this statute alongside older common law references. These are entirely distinct bodies of material. The encyclopedia entry at contracts_181 addresses the regulatory framework; the interpretive rule above addresses the common law.
Trap for researchers: Full-text searches on "can" across the corpus will generate noise at extraordinary volume. This term is too common in ordinary legal prose to serve as a useful search string without significant qualification. Narrow searches to "as soon as can," "can-spam," or specific doctrinal contexts.
Historical Dictionary Support
Black's Law Dictionary encodes the most practically useful legal proposition associated with this term: the presumption that a promise conditioned on ability is treated as a present obligation, with the supporting principle that the law presumes every person solvent. This was a meaningful rule of construction in debt enforcement, particularly in the early republic when conditional promises were used to defer obligations.
Burrill's entry is a misfiling or scanning artifact. The text under "CAN" in Burrill actually addresses "CAMPERS" and "CHAMPERTY" — Latin and French law terms relating to champart and maintenance. This is an editorial or indexing error in the source. Researchers relying on Burrill for this term will find nothing relevant to "can" as an auxiliary verb or legal concept.
Anderson directs readers to CASE (definition 4), suggesting a linkage to legal capacity or the right to bring an action. This cross-reference is too sparse to reconstruct Anderson's full intent, but it points toward "can" as carrying procedural significance in contexts of legal standing or actionability.
None of the historical dictionaries address "can" in its modern regulatory or drafting-convention sense. That usage postdates all three sources.
Encyclopedia Cross-Reference
Contracts & Commercial Law Encyclopedia: Consumer Protection — Telemarketing Sales Rule and CAN-SPAM (contracts_181)