ARGUMENTS and COGENCY
An argument is:
A set of one or more propositions (or claims), called premises, advanced as proof or evidence for
another proposition, called the conclusion.
A cogent (or good) argument must meet three conditions. If any of the conditions is not met, the
argument is fallacious:
(a) the reasoner(s) must be warranted in believing the premises
(b) the argument must proceed according to a correct principle of reasoning
(c) one must argue in good faith and not suppress relevant evidence.
If these three conditions are met, one is warranted, or justified, in believing the argument's
N.B. Argument layeredness.
Almost every known human carcinogen causes cancer in animals. Thus it is reasonable to expect
that compounds that cause cancer in animals are also human carcinogens.
A deductive argument:
1. All Greeks are human beings.
2. All Athenians are Greeks.
3. Therefore, all Athenians are human beings.
An inductive argument:
1. X 1 X 2 X 3 . . . Charlieave red hair and hot tempers.
2. X Dianehas red hair.
3. Therefore, (probably) Diane has a hot temper.
An inductive argument with a conclusion we know would be true:
1. X 1 X 2 X 3 . . . Charliere both smokey and fiery.
2. X is smokey.
3. Therefore, my house is fiery. MORAL REASONING
Simple Case: Murder
Jennifer hits Michael over the head with a baseball bat.
Moral reasoning typically involves both factual and moral premises.
Fact: This action was a murder.
Moral principle or premise: Murder is wrong.
Conclusion: This action was wrong.
To justify the factual premise:
1. Murder is killing a human being with malice aforethought. (Definition)
2. Jennifer killed Michael. (Fact known by perception or another means)
3. Michael was human. (Fact)
4. Jennifer's act was premeditated and malicious. (Fact)
To justify the moral principle, we may argue from above or from below.
From below, we argue from instances:
· This murder was wrong.
· That murder was wrong.
· Murder is wrong.
From above, we argue from broader principles: we need a moral theory. Often this takes the