The Two Branches of Logic
- Deduction - the conclusion follows necessarily from he premise(s)
- Categorical (Aristotelian) Logic - the logical relationship between the terms of categorical propositions
- Propositional (Sentential) Logic - the logical relationships between statements
- Predicate Logic - the logical relationships between quantifiable variables
- Modal Logical - The logical relationship between modally modified propositions
- Induction - a conclusion follows with a degree of probability from the premise(s)
- Arguments by Analogy (legal and moral reasoning)
- Arguments from Authority (deferring to expert consensus in a field/peer review)
- Arguments from Causation/Prediction (Mill’s Method)
- Arguments from Probability (How to Win in Vegas)
- Arguments from Statistical Evidence/Generalization (social scientific method)
- Arguments from Hypothesis (the scientific method)
- Arguments from Signs/Symbols
- Evaluating Arguments - what makes arguments “good” or “bad”?
- Deductive Arguments - a conclusion follows necessarily from the premise(s)
- Valid - the from of the argument is correct (i.e., if the premises are assumed to be true, then the conclusion cannot be false)
- Sound - the argument is valid (i.e., the form is correct) and the premises are true
- Inductive Arguments - a conclusion follows with a degree of probability from the premise(s)
- Strong - the premises are sufficient, relevant, and clear enough to make the conclusion more likely than not
- Cogent - the argument is strong (i.e., the premises are sufficient, relevant, and clear enough to make the conclusion more likely than not), and the premises are true
Note: Remember, arguments are never true or false. Only a proposition or statement can have a truth-value.
Arguments are either valid and sound, or strong and cogent depending on whether they are inductive or deductive.
Back to the Main Page | Back to PHI 1013