LOGIC DEFINITIONS

Philosophy 1020: Introduction to Logic
(See exercise III p 14)

1.   Statement: a sentence that is true or false.

2.   Proposition: the same as a statement.

3.   Premiss: a statement / proposition that claims to provide evidence for the conclusion of an argument.

4.   Conclusion: a statement / proposition of an argument that the premisses claim to support.

5.   Argument: a group of statements where the premisses claim to provide evidence for the conclusion. There can only be one conclusion, but there can be one or more premisses.

6.    Inference: the same as an argument.

7.   Conditional Statement: an if … then … statement. (p 21) If (antecedent), then (consequent). For example: If the premisses of an inductive argument are all true (antecedent), then the conclusion is probably true (consequent). If the premisses of a deductive argument are all true (antecedent), then the conclusion is necessarily true. If the premisses of a deductive argument are all true (antecedent), then it is impossible for the conclusion to be false.

Note: conditional statements are not arguments, but they can be a premiss or conclusion of an argument.

Go over punctuation.

 

8.   Disjunctive Statement: an either … or … statement. (p 34) Either  (left disjunct)  or  (right disjunct).

9.   Syllogism: an argument with only two premisses. (p 34)

10. Hypothetical Syllogism: a syllogism with a conditional statement for one or more of its premisses. (p 34) Example Fox News

11. Categorical Syllogism: a syllogism where each proposition begins with all, no, or some. (p 34)

12. Disjunctive Syllogism: a syllogism with a disjunctive statement for one or more of its premisses. (p 34) Example Global Warming

13. Deductive Argument: an argument that claims that it is impossible for the conclusion to be false if the premisses are all true. (p 42)

14. Valid Deductive Arguments: an argument where it is impossible for the conclusion to be false if the premisses are true. The conclusion follows necessarily from the premisses.

15. Invalid Deductive Argument: an argument where it is possible for the conclusion to be false if the premisses are true. (see top of p 45)

16. Sound Argument: a valid deductive argument with all true premisses. (p 45)

17. Unsound Argument: a deductive argument that is invalid or has at least one false premiss.

18. Inductive Argument: an argument that claims that if the premisses are true, then the conclusion is probably true. (p 32 and 45)

19. Strong Inductive Argument: an inductive argument where if the premisses are true, then the conclusion is probably true. (p 45)

20. Weak Inductive Argument: an inductive argument where if the premisses are true, then the conclusion is not probably true. (p 45)

21. Cogent Argument: a strong inductive argument with true premisses. (p 48)