Argumentum A Simili Valet In Lege

Argumentum A Simili Valet In Lege
Argumentum A Simili Valet In Lege
Quick Summary of Argumentum A Simili Valet In Lege

Argumentum a simili valet in lege is a legal principle that states that an argument from similarity is valid in law. This principle allows for the use of analogical reasoning in legal arguments, where a similar case or situation can be used as a precedent to support a legal claim or interpretation. It suggests that if two cases or situations are similar in relevant aspects, then the legal reasoning and outcome applied to one case can be applied to the other. This principle is often used in common law systems to establish legal principles and provide guidance in cases where there is no specific statute or precedent. However, it is important to note that the application of this principle requires careful analysis of the similarities and differences between the cases to ensure that the analogy is appropriate and justifiable.

What is the dictionary definition of Argumentum A Simili Valet In Lege?
Dictionary Definition of Argumentum A Simili Valet In Lege

Argumentum A simili valet in lege is a Latin legal term that translates to “an argument from similarity is valid in law.” This principle suggests that if two situations are similar in relevant aspects, then the legal treatment of one situation should be similar to the treatment of the other. It is a concept used in legal reasoning and argumentation to support the application of precedent or analogical reasoning in legal decision-making.

Full Definition Of Argumentum A Simili Valet In Lege

“Argumentum a simili valet in lege” is a Latin maxim that translates to “an argument from similarity is valid in law.” This principle is integral to legal reasoning, especially in common law systems where precedent and analogy play a crucial role. The use of analogy in legal contexts allows for the application of established principles to new, similar cases, ensuring consistency and fairness in judicial decisions. This overview explores the origins, applications, and implications of this maxim within the legal framework.

Historical Context

The maxim “argumentum a simili valet in lege” finds its roots in Roman law, where legal scholars and jurists often relied on analogical reasoning to fill gaps in written statutes. This approach was essential in a system where laws could not foresee every possible circumstance. The principle was later absorbed into medieval European legal thought and eventually became a cornerstone of common law reasoning in England.

Roman Law

In Roman law, analogy was a critical tool for jurists. The Praetors, who were responsible for administering justice, frequently employed analogical reasoning to interpret and apply the law. For instance, if a statute addressed a particular scenario, jurists would apply the same reasoning to a similar but unanticipated situation. This method ensured that the law could adapt to new circumstances while maintaining coherence and consistency.

Medieval and Early Modern Periods

During the medieval period, the revival of Roman law in Europe, particularly through the work of the glossators and commentators, reinforced the importance of analogical reasoning. English common law, developing independently yet influenced by these broader European trends, also embraced analogy as a method of legal reasoning. Judges and lawyers in England relied on analogical arguments to interpret the law, especially in cases where statutes were silent or ambiguous.

Conceptual Framework

The principle of “argumentum a simili valet in lege” operates on the assumption that similar cases should be treated similarly. This section delves into the conceptual underpinnings of analogical reasoning in law, highlighting its strengths and potential pitfalls.

Analogical Reasoning

Analogical reasoning involves drawing parallels between two or more cases based on their similarities. In legal contexts, this means applying the rationale of a previously decided case (the precedent) to a current case that shares similar facts or issues. The strength of an analogical argument depends on the degree of similarity between the cases and the relevance of the shared characteristics to the legal principles involved.

Key Components of Analogical Reasoning

  1. Identification of Similarities: The first step is to identify the similarities between the current case and the precedent. This involves a careful examination of the facts, legal issues, and outcomes of the cases.
  2. Relevance of Similarities: Not all similarities are legally relevant. The relevant similarities are those that affect the application of legal principles or rules. For example, in contract law, the similarities between the terms of agreements might be more relevant than the parties involved.
  3. Application of Legal Principles: Once relevant similarities are identified, the legal principles applied in the precedent case are used to resolve the current case. This ensures consistency and predictability in legal decisions.

Advantages of Analogical Reasoning

  • Consistency: By applying the same principles to similar cases, the law remains consistent and predictable, which is fundamental for the rule of law.
  • Flexibility: Analogical reasoning allows the law to adapt to new situations and changing social conditions without the need for constant legislative intervention.
  • Equity: Treating similar cases alike promotes fairness and justice, as parties can expect similar treatment under similar circumstances.

Potential Pitfalls

  • Subjectivity: Determining whether cases are sufficiently similar can be subjective, leading to inconsistent applications.
  • Over-reliance on Precedent: Excessive reliance on analogy can stifle legal innovation and adaptation to new realities.
  • Complexity: Analogical reasoning can be complex, requiring a deep understanding of both the facts and the underlying legal principles.

Application in Common Law

In common law systems, where judicial decisions create binding precedents, the principle of “argumentum a simili valet in lege” is particularly significant. This section examines how analogy functions within the common law tradition, focusing on its role in judicial reasoning and the creation of precedent.

Judicial Reasoning

Judges in common law systems often use analogical reasoning to decide cases. When faced with a novel issue, a judge will look for similar cases that have been previously decided. By drawing analogies, the judge can apply established legal principles to the new case, ensuring that the decision aligns with existing law.

Case Example

A classic example of analogical reasoning in common law is the landmark case of Donoghue v Stevenson (1932), which established the modern concept of negligence. In this case, the court extended the principles of duty of care from cases involving direct contractual relationships to situations where no contract existed, based on the similarity of the duty to avoid harm.

Creation of Precedent

Precedents are established through judicial decisions, and these precedents serve as analogies for future cases. When a higher court decides a case, the principles and rules established become binding on lower courts within the same jurisdiction. Future cases with similar facts will be decided in accordance with these precedents, ensuring consistency in the application of the law.

Binding vs. Persuasive Precedents

  • Binding Precedents: Decisions made by higher courts that must be followed by lower courts in the same jurisdiction.
  • Persuasive Precedents: Decisions from other jurisdictions or lower courts that are not binding but may influence a judge’s decision.

Challenges and Criticisms

While analogical reasoning is fundamental to common law, it faces several challenges and criticisms. Critics argue that it can lead to judicial conservatism, where courts are reluctant to depart from established precedents even when societal conditions change. Additionally, the complexity of analogical arguments can make legal reasoning less transparent and accessible to non-lawyers.

Application in Civil Law

Although civil law systems rely more heavily on codified statutes, analogical reasoning still plays a role in legal interpretation and application. This section explores how analogy is used in civil law systems and compares it with its use in common law systems.

Role of Analogy in Civil Law

In civil law systems, where detailed codes and statutes predominate, analogical reasoning is used primarily to fill gaps in the law. When a statute is silent on a particular issue, judges may look to similar provisions or principles within the code to resolve the case.


In the German Civil Code (BGB), analogy is explicitly recognized as a method of legal reasoning. For instance, § analogical application is permitted when there is a gap in the law and a similar provision can be found elsewhere in the code.

Comparison with Common Law

While both legal systems use analogy, the context and extent of its application differ. In common law, analogical reasoning is central to judicial decision-making and the development of precedent. In contrast, civil law relies primarily on statutes, with analogy serving as a supplementary tool for interpretation.

Statutory Interpretation

Civil law judges use analogical reasoning primarily in the context of statutory interpretation, ensuring that the application of the law remains coherent and consistent with the broader legal framework.

Critiques and Limitations

Despite its importance, the principle of “argumentum a simili valet in lege” is not without its critics. This section examines some of the main critiques and limitations associated with analogical reasoning in legal contexts.

Subjectivity and Bias

One of the primary critiques is that analogical reasoning can be highly subjective. The determination of whether cases are sufficiently similar is often left to the discretion of judges, which can introduce personal biases and lead to inconsistent outcomes.

Evolution of Law

Another criticism is that an over-reliance on analogical reasoning can hinder the evolution of the law. By focusing too much on past decisions, courts may be less inclined to adapt the law to new social and technological realities. This can result in a legal system that is slow to respond to change.

Complexity and Accessibility

Analogical reasoning can also be complex and difficult for non-lawyers to understand. This complexity can create barriers to access to justice, as individuals may find it challenging to predict how the law will be applied to their specific circumstances.


“Argumentum a simili valet in lege” is a fundamental principle of legal reasoning, playing a crucial role in both common law and civil law systems. By allowing judges to apply established principles to new and similar cases, this maxim ensures consistency, fairness, and adaptability in the law. However, it also faces significant challenges, including subjectivity, potential stifling of legal innovation, and complexity. Understanding these dynamics is essential for appreciating how analogical reasoning shapes legal decision-making and the development of the law.


In summary, the principle of “argumentum a simili valet in lege” underscores the importance of analogy in legal reasoning. It facilitates the application of existing legal principles to new situations, promoting consistency and fairness. However, it also requires careful and judicious application to avoid subjectivity and ensure that the law evolves in response to new challenges. This overview highlights the enduring significance of this principle in the legal landscape, providing a comprehensive understanding of its role and implications.

Related Phrases
No related content found.

This site contains general legal information but does not constitute professional legal advice for your particular situation. Persuing this glossary does not create an attorney-client or legal adviser relationship. If you have specific questions, please consult a qualified attorney licensed in your jurisdiction.

This glossary post was last updated: 8th June 2024.

Cite Term

To help you cite our definitions in your bibliography, here is the proper citation layout for the three major formatting styles, with all of the relevant information filled in.

  • Page URL:
  • Modern Language Association (MLA):Argumentum A Simili Valet In Lege. DLS Solicitors. June 23 2024
  • Chicago Manual of Style (CMS):Argumentum A Simili Valet In Lege. DLS Solicitors. (accessed: June 23 2024).
  • American Psychological Association (APA):Argumentum A Simili Valet In Lege. Retrieved June 23 2024, from website:
Avatar of DLS Solicitors
DLS Solicitors : Family Law Solicitors

Our team of professionals are based in Alderley Edge, Cheshire. We offer clear, specialist legal advice in all matters relating to Family Law, Wills, Trusts, Probate, Lasting Power of Attorney and Court of Protection.

All author posts