LessonsDemonstration and the Six Kinds of Certain PremisesQuiz

Calling premises “certain” is not sufficient; their warrant must actually be established, and the argument's logical form must be productive.

For example:
1. Every integer divisible into two equal integers is even.
2. Four is divisible into two equal integers.
Conclusion: Four is even.

Here both the meanings and inferential relation are clear. The concept of evenness supplies the relevant basis.

If a merely probable statement were inserted into the same pattern, the inference might still be valid, but its conclusion would not thereby gain demonstrative certainty.

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Using the six sources in demonstration

Demonstration and the Six Kinds of Certain Premises

Calling premises “certain” is not sufficient; their warrant must actually be established, and the argument's logical form must be productive.

For example:
1. Every integer divisible into two equal integers is even.
2. Four is divisible into two equal integers.
Conclusion: Four is even.

Here both the meanings and inferential relation are clear. The concept of evenness supplies the relevant basis.

If a merely probable statement were inserted into the same pattern, the inference might still be valid, but its conclusion would not thereby gain demonstrative certainty.