Nepedia
Back to Discover
Advanced Reader
🔢

Informal logic

math Maturity 5-7 Next article →

Informal logic is a branch of philosophy that studies how we reason using natural language. Unlike formal logic, which relies on strict mathematical symbols, informal logic focuses on everyday discourse. It provides standards and procedures to analyze, interpret, evaluate, and construct arguments. While some scholars dispute its exact definition, it is often seen as a tool for understanding how people communicate ideas. It helps us move beyond simple formulas to look at the actual substance of human reasoning.

Argument terminology used in logic (en)
Argument terminology used in logic (en)

To understand how informal logic works, one must distinguish it from formal logic. In modern formal logic, the focus is on validity. An argument is valid if the conclusion must be true whenever the premises are true. This is a very strict requirement. Informal logic often deals with conductive arguments instead. These are arguments where the conclusion is supported by evidence, even if it is not mathematically certain. In a legal setting, for example, a person might be sentenced if a conclusion is true beyond a reasonable doubt. This type of reasoning relies on an accumulation of evidence rather than pure deduction.

Scholars use different ways to describe the concept of "form" in this context. Researchers Barth and Krabbe identified three distinct senses of the term. The first sense refers to metaphysical forms, like those described by Plato. Most traditional logic is considered informal in this broad sense. The second sense refers to the logical form of sentences, which is the core of formal logic. Informal logic rejects this sense as the primary way to judge arguments. The third sense refers to regulated procedures or rules. In this way, informal logic can actually be formal. It follows specific rules and criteria to ensure a discussion is conducted fairly and effectively.

History shows that informal logic emerged as a distinct field in the mid-20th century. It grew because many educators felt that symbolic logic was too difficult for general students. In 1971, Howard Kahane published a significant textbook titled "Logic and Contemporary Rhetoric." His goal was to help students navigate misleading rhetoric in politics and the media. He wanted to promote discourse that seeks truth rather than just persuasion. Other important works followed, such as Michael Scriven’s "Reasoning" in 1976. Ralph Johnson and J. Anthony Blair also contributed with their 1977 book, "Logical Self-Defense."

The field became more established during the First International Symposium on Informal Logic in 1978. At this meeting, Blair and Johnson identified thirteen core issues for the discipline. These issues included the theory of fallacy and the ethics of argumentation. They also discussed the problem of missing premises and the role of context. Since 1983, the journal "Informal Logic" has served as a primary publication for the field. Other journals, such as "Argumentation," also support this area of study. Despite its growth, some scholars like David Hitchcock argue the name is unfortunate. He suggests that "philosophy of argument" might be a more accurate title.

Informal logic is closely linked to the concept of critical thinking. Many people use these two terms interchangeably, but they are not exactly the same. Critical thinking is a much broader discipline. It involves the active interpretation and evaluation of all forms of communication. It requires skills like assessing new information and clarifying meanings. Informal logic provides the "intellectual spine" for this process by focusing on argumentation. While informal logic helps you evaluate an argument's strength, critical thinking includes the broader attitudes and skills needed to find and use information.

Today, the study of informal logic remains a vital part of many educational systems. It connects to various fields, including argumentation theory and the thinking skills movement. By studying how arguments are built and where they fail, students learn to dissect complex ideas. This helps them avoid the deceptions found in many types of public speech. Whether analyzing a political debate or a scientific inquiry, these tools allow for a deeper understanding of how we reach conclusions in our daily lives.

660 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (1)
File:Argument terminology used in logic (en).svg
Argument terminology used in logic (en).svg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.