Presentation is loading. Please wait.

Presentation is loading. Please wait.

Contingent A statement is contingent iff it is neither a logical truth nor a contradiction.

Similar presentations


Presentation on theme: "Contingent A statement is contingent iff it is neither a logical truth nor a contradiction."— Presentation transcript:

1

2 Contingent A statement is contingent iff it is neither a logical truth nor a contradiction.

3 Contingent A statement is contingent iff it is neither a logical truth nor a contradiction. So the output row for a contingent statement must contain at least one F and at least one T.

4 Contingent A statement is contingent iff it is neither a logical truth nor a contradiction. So the output row for a contingent statement must contain at least one F and at least one T. Sample contingent statement: P>Q

5 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T.

6 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible.

7 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. There is also no proof test for invalidity.

8 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. with a tree:The tree for -A is open and the tree for A is open.

9 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. with a tree:The tree for -A is open and the tree for A is open. Common Mistake: The tree has one open and one closed branch.

10 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. with a tree:The tree for -A is open and the tree for A is open. Common Mistake: The tree has one open and one closed branch. WRONG! You need to do TWO trees.

11 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. with a tree:The tree for -A is open and the tree for A is open. A is not a logical truth and A is not a contradiction.

12 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. with a tree:The tree for -A is open and the tree for A is open. A is not a logical truth and A is not a contradiction.

13 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. with a tree:The tree for -A is open and the tree for A is open. A is not a logical truth and A is not a contradiction.

14 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. with a tree:The tree for -A is open and the tree for A is open. Sample: Here are trees that show that P>Q is contingent. -(P>Q) P -Q P>Q -P Q open

15 Contingent To show a statement A is contingent... with a table: The output row for A has a F and a T. with a proof:No proof test is possible. with a tree:The tree for -A is open and the tree for A is open. For more click here


Download ppt "Contingent A statement is contingent iff it is neither a logical truth nor a contradiction."

Similar presentations


Ads by Google