Illicit Major Fallacy Detector

Detect a major term distributed in a categorical conclusion but undistributed in its major premise.

Description

Categorical propositions use A for universal affirmative, E for universal negative, I for particular affirmative and O for particular negative.

Categorical propositions use A for universal affirmative, E for universal negative, I for particular affirmative and O for particular negative. The illicit major fallacy distributes the predicate P of the conclusion without distributing that term in its premise.^[1]

The tool returns illicitMajor. Interpret the result under the rule and assumptions below; an encoded premise’s truth is not independently established.

When to use Illicit Major Fallacy Detector

Use this for the following task: Detect a major term distributed in a categorical conclusion but undistributed in its major premise. Prepare the specified logical encoding before running the check or transformation.

How to use Illicit Major Fallacy Detector and understand its results

Prepare the requested Boolean values, complete truth-table rows, or identifier atoms. An atom is a name such as p or premise_1, not a natural-language sentence.
Enter majorKind, conclusionKind, figure according to the field table, then run the tool.
Read illicitMajor. Use the matching rule, assignment order or nonempty-class assumptions below to interpret the result.
For a false check, inspect the supplied encoding and matching rule. A well-formed false result is different from an input error.

Input field	Meaning	Value type and bounds	Requirement
majorKind	Major proposition kind	string; choices "A", "E", "I", "O"	Required
conclusionKind	Conclusion proposition kind	string; choices "A", "E", "I", "O"	Required
figure	Syllogism figure	integer; minimum 1; maximum 4	Required

Choose majorKind, conclusionKind and figure. Locate the relevant term in its premise and compare premise and conclusion distribution using A/E/I/O rules.

illicit major ⇔ conclusion distributes term AND premise does not

The symbols and boundary conditions refer to the supplied fields and the implementation described above.

Output field	Meaning	Value type
illicitMajor	Illicit Major	boolean

json

{
  "input": {
    "majorKind": "A",
    "conclusionKind": "E",
    "figure": 1
  },
  "output": {
    "illicitMajor": true
  }
}

Limitations and assumptions

The flag checks one necessary validity rule. A false result does not certify a whole syllogism.

The supplied encodings must represent the intended propositions or classes. No natural-language parsing or assessment of empirical premise truth is performed. Malformed input gives a tool error rather than a logical false result.

Alternative or Complementary methods

Choose Undistributed Middle Fallacy Detector when you need its operation: Detect an undistributed middle term in the two premises of a standard categorical syllogism. Choose Illicit Minor Fallacy Detector for the complementary operation: Detect a minor term distributed in a categorical conclusion but undistributed in its minor premise.

Background reference: Categorical Logic.

References

Categorical Logic — Philip B. Stark, University of California Berkeley

Similar or alternative tools

Undistributed Middle Fallacy Detector
Detect an undistributed middle term in the two premises of a standard categorical syllogism.
Illicit Minor Fallacy Detector
Detect a minor term distributed in a categorical conclusion but undistributed in its minor premise.