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Per se

Per se is a Latin phrase meaning "by itself," "in itself," or "of itself," adopted into English as an adverb to denote something considered intrinsically, inherently, or without external qualification.^[1] The term originates from Latin, where per signifies "by" or "through" and se is the reflexive pronoun for "itself," with its earliest documented use in English dating to 1574.^[1] In legal contexts, per se describes rules or violations that are inherently actionable without needing additional evidence of harm, unreasonableness, or specific impact, streamlining judicial analysis.^[2] For instance, in antitrust law, certain restraints of trade, such as price-fixing agreements, are deemed illegal per se due to their presumed anticompetitive effects.^[2] Similarly, in tort law, negligence per se occurs when a defendant's violation of a statute or regulation automatically breaches the duty of care owed to the plaintiff, presuming the law was designed to protect against the type of harm suffered.^[3] In philosophy, particularly Aristotelian metaphysics, per se (from Greek kath' auto, meaning "in itself" or "by itself") refers to essential predications or properties that inhere in a subject by its very nature, distinguishing them from accidental attributes.^[4] Aristotle, in works like the Posterior Analytics and Metaphysics, uses per se to categorize connections where a predicate belongs to a subject essentially, such as "even" to "two" in the first mode of per se predication (part of the essence or definition), or necessary properties like "sensible" (capable of sensation) to "animal" in the second mode (following necessarily from the essence). This concept underpins scientific demonstrations and essential definitions, influencing medieval scholasticism and later ontological discussions.^[4] Beyond specialized fields, per se appears in general English usage to isolate an idea or quality from its broader context, often clarifying that no inherent fault or value exists independently. Common examples include phrases like "not bad per se," indicating the subject is neutral on its own merits. Its integration into modern language reflects the enduring influence of Latin on legal, academic, and everyday discourse.^[1]

Etymology and Definition

Latin Origins

The phrase "per se" derives from classical Latin per sē, composed of the preposition per meaning "by" or "through" and the reflexive pronoun sē referring to "itself," "himself," "herself," or "themselves."^[5] This construction emphasizes intrinsic qualities or actions independent of external factors, translating literally as "by itself" or "in itself."^[5] Grammatically, per functions as a preposition governing the accusative case to indicate agency or means, while sē serves as the third-person reflexive pronoun in the accusative form, highlighting self-referential or inherent processes.^[6] The combination forms an idiomatic expression denoting something "in and of oneself," often used to underscore autonomy or essential nature without additional qualifiers.^[6] The phrase appears in classical Latin literature, including works by Cicero, where it conveys inherent value or self-sufficiency; for instance, in De Finibus Bonorum et Malorum (5.23), Cicero employs per se to describe pleasures as desirable "by themselves" (voluptates per se expetendae).^[7] From ancient Roman texts, per se persisted into medieval Latin, where it influenced scholastic philosophy, such as in discussions of self-evident truths (per se nota) that require no further proof.^[8] This Latin construction later entered English through scholarly translations of classical and medieval works, retaining its original form and sense of inherent quality.^[5]

Core Meaning in English

In English, "per se" is a Latin adverbial phrase adopted as a loanword, literally translating to "by itself," "in itself," or "of itself," emphasizing the inherent or intrinsic nature of something without regard to external relations or contexts.^[1] This core sense highlights an isolated consideration of a subject, focusing on its standalone qualities rather than comparative or relational aspects.^[5] The phrase entered English usage in the 1570s, primarily through translations of Latin texts in scholarly and intellectual works, marking its integration into the language during the Renaissance period.^[1] It retains a formal, Latinate tone that distinguishes it from more vernacular expressions, often appearing in academic, legal, or precise discourse to underscore self-contained meaning. Common English synonyms for "per se" include "as such," "essentially," or "by its very nature," though these lack the phrase's concise, authoritative resonance derived from its classical roots.^[1] In pronunciation, it is typically rendered as /pər ˈseɪ/ in American English or /pɜːr ˈseɪ/ in British English, adapting the original Latin elocution while aligning with English phonetic patterns.^[1]

Philosophical Contexts

Aristotelian Usage

In Aristotle's Posterior Analytics and Metaphysics, the term "per se" (translating the Greek kath' auto, meaning "according to itself" or "in its own right") refers to essential predication, where attributes belong to a subject inherently through its nature or essence, rather than by accident or coincidence.^[9]^[10] This concept is central to Aristotle's metaphysics and logic, distinguishing necessary, intrinsic connections from contingent ones, and forms the basis for understanding substance, causation, and scientific explanation. Aristotle distinguishes two primary modes of per se predication in Posterior Analytics I.4 (73a34–b5), essential for scientific demonstration. The first mode occurs when the predicate is contained in the definition (or essence) of the subject, as "animal" is part of the definition of "human" (including genus-species relations).^[9] The second mode is when the subject is contained in the definition of the predicate, pertaining to proper attributes (propria) that necessarily follow from the essence, as "number" is part of the definition of "odd" (since oddness applies essentially to numbers).^[9] This framework contrasts sharply with "per accidens" (incidental or accidental) predication. Per se causes and effects are intrinsic and necessary, as when fire heats per se because heating is essential to its nature as a hot substance.^[9] In contrast, per accidens connections are coincidental and non-essential, such as a house builder being pale, where paleness has no inherent tie to the act of building.^[9] In Metaphysics Δ.7 (1017a22–30), Aristotle extends this to being per se, which is predicated in as many ways as the categories (substance, quality, quantity, etc.), underscoring that essential being avoids accidental multiplicity.^[10] In the context of demonstration, per se predication is indispensable for achieving scientific knowledge (epistēmē). As outlined in Posterior Analytics I.6–13, true demonstrations rely on syllogisms with premises that connect terms essentially, ensuring the conclusion follows necessarily from the subject's nature rather than chance.^[9] For instance, proving that the angles of an isosceles triangle equal two right angles proceeds per se through the essential property of all triangles, yielding universal and certain understanding.^[9] Without such intrinsic links, knowledge remains opinion or mere fact, lacking explanatory depth.^[11]

Medieval and Later Interpretations

In medieval scholastic philosophy, Thomas Aquinas employed the concept of per se to denote essential necessity and self-existence, particularly in his cosmological arguments for God's being. In the Summa Theologica, Aquinas distinguishes between contingent beings, which depend on external causes for their existence, and a necessary being that exists per se, meaning it possesses its necessity intrinsically without reliance on anything else. This per se necessary being serves as the ultimate cause of all other necessities, identified as God, thereby grounding the third way of demonstrating divine existence. Aquinas further applies per se to self-evident propositions, where the predicate is contained within the subject's essence, as in the case of God's existence being per se notum in itself, though not immediately evident to human intellect due to our limited grasp of divine essence. Building on Boethius's translations and commentaries of Aristotle, medieval logicians refined per se predication as a key element in syllogistic reasoning and the analysis of universals, influencing the nominalism-realism debates. Boethius's work in De Topicis Differentiis and his Aristotelian commentaries established per se predication as occurring when a predicate belongs essentially to a subject, either through the subject's inclusion in the predicate's definition (per se primo modo) or vice versa (per se secundo modo), distinguishing it from accidental predication. This framework, transmitted through scholastic figures like Peter Abelard, shaped discussions on whether universals exist per se as real entities (realism) or merely as names (nominalism), with per se denoting intrinsic relations that underpin necessary truths in propositions such as "man is (an) animal."^[12] Later scholastics, such as Robert Kilwardby, extended this to modal logic, classifying necessities as per se when rooted in essential definitions, thereby affecting debates on the ontological status of properties.^[13] During the Enlightenment, Immanuel Kant's notion of the Ding an sich (thing-in-itself) echoed the scholastic per se by emphasizing reality independent of sensory representation, though Kant shifted the focus to noumenal existence beyond phenomenal experience. In this framework, the Ding an sich represents objects that are things per se, possessing determinate reality as the terminus of intellectual acts, without direct accessibility to human cognition.^[14] This adaptation diverged from medieval usage by prioritizing epistemological limits over ontological necessity, yet retained the core idea of intrinsic being unconditioned by external relations. In 20th-century analytic philosophy, per se appeared in discussions of intrinsic properties, with Willard Van Orman Quine invoking it to critique essentialism while analyzing attributes independent of relational contexts, as in his rejection of de re modalities that treat properties as per se necessary. Ludwig Wittgenstein, in his later works, alluded to per se meanings in language games, where concepts gain significance not intrinsically but through use, subtly undermining scholastic notions of self-evident per se predications.^[15]

Legal Applications

Antitrust and Competition Law

In United States antitrust law, the term "per se" refers to agreements or practices deemed inherently anticompetitive and thus illegal under Section 1 of the Sherman Act without requiring a detailed "rule of reason" analysis to assess their actual market effects or procompetitive justifications. This approach presumes that certain conduct, such as horizontal price-fixing among competitors, invariably harms competition by reducing output, raising prices, or allocating markets, eliminating the need for plaintiffs to prove specific anticompetitive impacts. The per se rule streamlines enforcement by treating these violations as presumptively unreasonable, contrasting with the rule of reason established in Standard Oil Co. of New Jersey v. United States (1911), which evaluates restraints based on their overall economic context. The doctrine's formalization built on early cases recognizing presumptive illegality for egregious restraints. In Dr. Miles Medical Co. v. John D. Park & Sons Co. (1911), the Supreme Court held that vertical resale price maintenance agreements—where manufacturers dictate minimum prices to distributors—are illegal per se, as they eliminate intrabrand price competition without redeeming benefits.^[16] However, this ruling was overruled in Leegin Creative Leather Products, Inc. v. PSKS, Inc. (2007), which subjected vertical minimum resale price maintenance to rule of reason analysis.^[17] This was extended to horizontal cartels in United States v. Trenton Potteries Co. (1927), where the Court explicitly deemed price-fixing agreements per se violations, rejecting any defense based on "reasonable" prices. The per se framework was further clarified in Northern Pacific Railway Co. v. United States (1958), which applied it to tying arrangements, stating that such practices are "conclusively presumed to be unreasonable" due to their inherent tendency to foreclose competition, particularly when involving market power.^[18] Subsequent rulings refined the rule's scope, shifting some vertical restraints away from per se treatment. In Continental T.V., Inc. v. GTE Sylvania Inc. (1977), the Supreme Court overruled prior precedents by subjecting non-price vertical restraints, like territorial allocations, to rule-of-reason scrutiny, emphasizing their potential to promote interbrand competition. Vertical price restraints, previously per se illegal under Dr. Miles, were similarly shifted to the rule of reason in Leegin (2007). Examples of per se violations under this regime include horizontal market division, bid rigging, and group boycotts, all presumed to lack procompetitive virtues. Internationally, the European Union's competition law employs a parallel concept under Article 101 of the Treaty on the Functioning of the European Union (TFEU), where restrictions "by object" are treated as inherently anticompetitive, akin to per se illegality, without needing an effects-based analysis. This includes practices like horizontal price-fixing or cartel agreements, presumed to harm the internal market's competitive functioning. The European Court of Justice has consistently applied this to ensure uniform enforcement, mirroring the U.S. emphasis on presumptive harm for naked restraints.

Broader Legal Contexts

In negligence law, the doctrine of negligence per se holds that an unexcused violation of a statute or regulation intended to protect public safety constitutes a breach of the duty of care, making the violator liable without further proof of negligence.^[19] This principle simplifies tort claims by treating statutory noncompliance as inherently negligent when the plaintiff belongs to the protected class and the harm is of the type the law seeks to prevent.^[19] A classic illustration involves traffic laws, such as speeding, where exceeding posted limits in a vehicle accident automatically establishes negligence if causation is shown.^[20] The seminal U.S. case Martin v. Herzog (1920) applied this doctrine when a driver's failure to display required headlights at night violated a vehicle statute, rendering the omission negligence per se and contributing to liability for the resulting collision.^[21] In contract law, agreements that contravene public policy are deemed void per se, meaning they are inherently unenforceable from inception without need for additional justification.^[22] Usurious contracts, which impose interest rates exceeding statutory maximums, exemplify this, as they exploit vulnerability and undermine economic fairness, rendering the entire agreement invalid in many jurisdictions.^[23] For instance, in Bank of the United States v. Owens (1829), the U.S. Supreme Court held a discounted note usurious and void ab initio, prohibiting recovery of principal or interest due to the inherent illegality.^[24] Constitutional law employs "per se" to denote presumptive invalidity for governmental actions burdening fundamental rights, triggering strict scrutiny review.^[25] Under this standard, such infringements—such as restrictions on speech, religion, or equal protection based on suspect classifications—are deemed unconstitutional unless narrowly tailored to serve a compelling state interest, shifting the burden to the government to justify the measure.^[25] This approach ensures heightened protection for core liberties, as seen in cases involving racial discrimination, where classifications are per se suspect and rarely upheld.^[26] In comparative contexts, English common law developed general principles of negligence independent of privity, as in Donoghue v. Stevenson AC 562, where the House of Lords established a duty of care owed by manufacturers to foreseeable consumers for harm from defective products. This influenced global tort law but differs from the U.S. negligence per se doctrine, which specifically presumes fault from statutory violations.

Modern Usage and Variations

Everyday Language Examples

In everyday language, "per se" serves to emphasize the intrinsic quality of something considered in isolation, without reference to external factors or associations. In contemporary journalism, particularly articles on technology ethics in the 2020s, the phrase clarifies nuances in debates about societal impacts. For instance, a 2024 New York Times report on youth mental health states: "Some scientists who study youth mental health say the evidence does not support the notion that social media is harmful per se," underscoring that the platform itself is not inherently damaging, but rather its patterns of use can be.^[27]

Common Misuses and Clarifications

A frequent error in using "per se" involves misspelling it as "per say," which arises from its pronunciation sounding like the English words "per" and "say."^[28] This variant has no established meaning in English and should be avoided in favor of the correct Latin-derived spelling.^[29] Another common pitfall is the overuse of "per se" in casual or non-specialized contexts, where it can come across as pretentious or unnecessary, particularly when simpler phrasing would suffice to indicate something "in itself" or "intrinsically." For instance, writers and speakers sometimes insert it to qualify statements without precisely addressing an intrinsic quality, diluting its precision; a more accurate application limits it to cases where the essence of the subject is under discussion apart from external factors. While "per se" often appears in negative constructions to soften critiques—such as "The policy is not problematic per se"—it is equally valid in positive contexts to affirm inherent qualities, as in descriptions of performance or value "in itself." Examples include agricultural breeding reports highlighting lines with "excellent per se performance" or "good per se grain yield," emphasizing standalone merits.^[30] Style guides recommend retaining italics for the phrase in formal writing to preserve its Latin origin, but advise against overuse to maintain clarity.^[31]

References

[1]
Definition of PER SE
### Summary of "Per Se" from Merriam-Webster
[2]
[PDF] The Rule of Reason and the per se Concept - Yale University
The current shibboleth of per se illegality in existing law conveys a sense of certainty, even of automaticity, which is delusive. The per se concept does not ...
[3]
per se
### Summary of "Per Se" in Legal Context
[4]
Per se - Origin & Meaning of the Phrase
### Etymology of "per se"
[5]
Chapter 13
per se is idiomatic for "in and of oneself." Per se is used per se in English today. 13. Note that secum, not cum se, is the proper Latin form. Home/Index ...
[6]
Full article: Intuitive cognition in the Latin medieval tradition
Feb 9, 2023 · These are truths which are known by virtue of themselves (per se nota), namely, “immediate propositions” in which the connection between ...
[7]
Posterior Analytics by Aristotle - The Internet Classics Archive
Posterior Analytics By Aristotle Written 350 B.C.E. Translated by G. R. G. Mure. Posterior Analytics has been divided into the following sections: Book I ...
[8]
Metaphysics by Aristotle - The Internet Classics Archive
The nature of a thing is a beginning, and so is the element of a thing, and thought and will, and essence, and the final cause-for the good and the beautiful ...Missing: online | Show results with:online
[9]
ARISTOTLE ON PREDICATION AND DEMONSTRATION ... - SciELO
It follows from this that the major premises and conclusions of the three demonstrations are per se2 predications. In each case one item is said to belong to a ...1. Demonstration... · 2. Natural Predication In... · 4. The Underlying Subject In...
[10]
Medieval Theories of the Syllogism
Feb 2, 2004 · The second type of per se predication (per se secundo modo) occurs when the definition of the predicate includes the subject. The best ...
[11]
Medieval Theories of Modality - Stanford Encyclopedia of Philosophy
Jun 30, 1999 · Robert Kilwardby's explanation is based on the view that convertible necessity premises are necessity propositions per se and not per accidens, ...
[12]
[PDF] Kant on Objects and Things - Studia Humanitatis
May 31, 2022 · I show that Kant's phrase Ding an sich denotes, not a type of thing, but a type of object: namely, an object which is per se a thing. My ...
[13]
[PDF] 2 History of Logic: Medieval
A proposition is per se nota because the predicate is included in the nature of the subject: for instance, Man is (an) animal, for animal is contained in ...
[14]
Dr. Miles Medical Co. v. John D. Park & Sons Co. | 220 U.S. 373 ...
The complainant, Dr. Miles Medical Company, an Indiana corporation, is engaged in the manufacture and sale of proprietary medicines, prepared by means of ...Missing: se | Show results with:se
[15]
Northern Pacific R. Co. v. United States | 356 U.S. 1 (1958)
It is not, as the Court intimates at one point in its opinion, that, under the Sherman Act, the tying clause is illegal per se; the per se illegality results ...
[16]
negligence per se | Wex | US Law | LII / Legal Information Institute
The most common application of negligence per se is traffic violations, where the driver is automatically considered negligent for violating the traffic code.
[17]
What's the Difference Between Negligence and Negligence Per Se?
Jun 17, 2024 · A typical example of negligence per se is a car accident involving a motorist's violation of traffic laws. If the motorist was speeding in ...
[18]
Martin v. Herzog | Case Brief for Law Students | Casebriefs
* The unexcused omission of the statute is negligence in itself, or negligence per se. In this case, there was an excuse for Plaintiff to be driving without ...Missing: doctrine | Show results with:doctrine
[19]
Contract Defense - Lawshelf
A contract is voidable if it is entered under duress. According to the Restatement of Contracts, “if a party's manifestation of assent is induced by an improper ...<|separator|>
[20]
[PDF] Bringing Order to Contracts Against Public Policy
Contracts voided on public policy grounds carry no legal obligations, therefore eviscerating their status as contracts. They are merely agreements.
[21]
Bank of the United States v. Owens | 27 U.S. 527 (1829)
Held that the contract was usurious and void, and that the bank could not recover of any of the parties to the discounted note. A fraud upon a statute is a ...
[22]
strict scrutiny | Wex | US Law | LII / Legal Information Institute
Strict scrutiny is a form of judicial review that courts in the United States use to determine the constitutionality of government action that burdens a ...Missing: per se
[23]
[PDF] An Empirical Analysis of Strict Scrutiny in the Federal Courts
Courts also use strict scrutiny to judge the constitutional validity of legislation infringing on fundamental rights under the ... laws invading fundamental ...
[24]
Donoghue v Stevenson Case Summary | LawTeacher.net
Donoghue v Stevenson established the duty of care, a key principle of negligence, even without a contract, and that manufacturers owe a duty to consumers.
[25]
[PDF] 50 Common Latin Phrases Every College Student Should Know
Per se: The direct translation of this term is "by itself" and it means just that when used in English as well. You could use it to say that you don't find ...
[26]
Researchers Say Social Media Warning Is Too Broad
Jun 19, 2024 · Some scientists who study youth mental health say the evidence does not support the notion that social media is harmful per se.
[27]
1984 and George Orwell's Other View of Capitalism – Modern Age
Jun 13, 2024 · By the early 1940s Orwell had also become deeply suspicious of economic collectivism per se: especially the threat it posed to intellectual ...
[28]
Grammars of Spoken English: New Outcomes of Corpus‐Oriented ...
Aug 6, 2025 · The spoken data are transcribed, recorded, and analyzed by frequency-based corpus linguistics tools (Leech, 2000) . ... per se. The article argues ...
[29]
Is it 'per say' or 'per se'? – Microsoft 365
Jun 27, 2024 · “Per say” is a common misspelling of the phrase “per se,” likely influenced by its pronunciation, which sounds similar. “Per se” means “by ...Missing: sources | Show results with:sources
[30]
Per Se vs Per Say: Which Is Correct? - LanguageTool
Rating 5.0 (3) Jun 12, 2025 · The correct spelling of the Latin phrase is per se, which translates to “by itself.” "Per say" is always a mistake.Missing: sources | Show results with:sources
[31]
The ongoing fuss over 'ongoing' - Sentence first - WordPress.com
Jul 28, 2011 · I agree that there's nothing wrong with the word per se; the only problem is its overuse among managers and bureaucrats, whose language is ...
[32]
CIMMYT releases 22 new maize inbred lines for the tropics and ...
Sep 5, 2013 · The line has good per se grain yield, good endosperm modification, and resistance to TLB. ... The line has good root strength, excellent per se ...
[33]
GUIDELINES ON STYLE FOR SCIENTIFIC WRITING - Sportsci.org
Do not use italics for foreign words and abbreviations common in scientific English, such as ad lib, per se, et al., via, ad hoc, post hoc, a priori, a ...