Definitions

Argument – A group of statements, some of which attempt to show that the other one is true (or other ones in the case of a complex argument).

Premise – A statement in an argument that provides a reason which is intended to support the conclusion.

Conclusion – The statement in an argument that the premises are intended to support.

Explanation – A group of statements which attempts to show how or why something is the case. In contrast, an argument attempts to show that something is the case (i.e., that the conclusion is true). (Like an argument, an explanation has two basic parts: the thing or event being explained, and the explanation of it. Unfortunately, we use the word ‘explanation’ to refer to both the whole and one of its parts, which is rather confusing.)

Simple Argument – An argument with only one conclusion, which all of the remaining statements attempt to support.

Complex Argument – An argument consisting in two or more simple argugments.

Deductive Argument – An argument that attempts to demonstrate with certainty that its conclusion is true.

Inductive Argument – An argument that attempts to demonstrate with probability that its conclusion is true.

Certainty – Lacking any doubt that something is true.

Probability – A greater than 50% chance that something is true, more likely than not.

Additive – The quality of an inductive argument, i.e., that it can be made stronger or weaker by adding additional premises.

Fallacy – A faulty or unsuccessful argument that is often mistaken for a good argument.

Informal Fallacy – A fallacy that is faulty due to the content of the premises rather than the form of the argument.

Formal Fallacy – A fallacious deductive or inductive argument that is faulty due to some flaw in the form of the argument.

The Two Criteria for a Successful Argument – (1) All of the premises are uncontroversially true. (2) The argument has the proper logical form (i.e., the proper connection between the premises and the conclusion).

Validity – (A) The proper logical form of a deductive argument: (B) its conclusion follows with certainty (C) from the meaning of the terms in the premises.

Strength – (A) The proper logical form of a inductive argument: (B) its conclusion follows with probability (C) since it is well supported by the empirical evidence in the premises.

Sound Argument – (A) A successful deductive argument: (B) it is valid and (C) has all true premises.

Cogent Argument – (A) A successful inductive argument: (B) it is strong and (C) has all true premises.

	Proper Logical Form	Successful Arguments (All True Premises and Proper Logical Form)	Unsuccessful Arguments (A False Premise or Improper Logical Form)
Deductive	Valid	Sound	Unsound
Inductive	Strong	Cogent	Uncogent
Informal Fallacy			All Fallacies are Unsuccessful

Sample Argument Forms

Barbara, AAA-1 (Valid)

All M are P.

All S are M.

Therefore, all S are P.

Darii, AII-1 (Valid)

All M are P.

Some S are M.

Therefore, some S are P.

Types of Claims

Theoretical/Descriptive	Practical/Normative
A. Formal (Necessary)	A. Moral (Necessary)
B. Empirical 1. Laws of Nature (Necessary) 2. Facts that can change (Contingent)	B. Pragmatic (Contingent)

Applicability of Arguments to Different Types of Statements (in degree of scope)

PA	All Statements
CS and AA		Categorical Statements
IG			Empirical Categorical Statements
IBE				Explanations
CA					Causal Explanations