Several theoretical and practical sessions in which propositional and predicate deductive logic will be studied for making and assessing legal reasoning, analogical reasoning, and inference to the best explanation, as well as for understanding and representing legal norms and Hohfeldian legal positions. In addition, defeasible legal reasoning in law will also be addressed, which is fundamental for the understanding of legal balancing. The videos are developed within the Task 3.8. as part of the Workpackage 3 of the ALF project.
The A Contrario Argument – Sara Azevedo
Title: The A Contrario Argument
Presenter: Sara Azevedo
ALF Partner Institution: Public Law Research Centre, University of Lisbon
In this short lesson, Sara Azevedo introduces the a contrario argument, a method of legal interpretation, explaining its structure and relevance in legal reasoning.
On A Fortiori Arguments – Gonçalo Fabião
Topic: On A Fortiori Arguments
Speaker: Gonçalo Fabião
Institution: Public Law Research Centre, University of Lisbon
In this short video lesson, Gonçalo Fabião examines the structure and use of a fortiori arguments in legal reasoning. He clarifies that a fortiori arguments should not be understood as a method of legal interpretation, nor as a tool for interpreting legal provisions. Furthermore, he argues that a fortiori arguments are not logically valid in the strict sense, as they do not ensure truth-preserving inferences.
Truth, Objectivity and Legal Statement – Tiago Rodrigues Barboza
Topic: Truth, Objectivity and Legal Statement
Speaker: Tiago Rodrigues Barboza
Institution: Public Law Research Centre, University of Lisbon
In this short video lesson, Tiago Rodrigues Barboza explores the relationship between truth, objectivity, and legal statements. He examines how the concept of truth relates to legal discourse and raises the central question: what is the relationship between truth and legal statements in the context of law?
What Can One Expect from Logic in Law? – Pedro Moniz Lopes
Topic: What Can One Expect from Logic in Law?
Speaker: Pedro Moniz Lopes
Institution: Public Law Research Centre, University of Lisbon
In this two-part short video lesson, Pedro Moniz Lopes reflects on the role of logic in legal thinking and explores what logic can realistically offer to legal practice. He outlines the advantages of understanding the fundamentals of logic when applied to legal reasoning and discusses the complex relationship—marked by both attraction and resistance—between logic and law.
Analogy in Legal Reasoning – Pedro Moniz Lopes
Title: Analogy in Legal Reasoning
Presenter: Pedro Moniz Lopes
Institution: Public Law Research Centre, University of Lisbon
In this concise and engaging lesson, Professor Pedro Moniz Lopes introduces the concept of analogy in law, explaining how analogical reasoning operates and why it plays a central role in legal interpretation and argumentation. He highlights the fact that analogy is a widely discussed and contested concept in legal theory and briefly outlines its main uses in legal reasoning.
Legal Balancing – Jorge Silva Sampaio
Topic: Legal Balancing
Speaker: Jorge Silva Sampaio
Institution: Public Law Research Centre, University of Lisbon
In this short lecture, Jorge Silva Sampaio explains how the concept of legal balancing is employed in legal reasoning. While logic plays a decisive role in identifying normative conflicts, it proves to be of limited practical use when it comes to resolving those conflicts—this is where the technique of balancing becomes essential.The operation of balancing becomes relevant for establishing preferences between conflicting norms and thus resolving normative conflicts.