Logic: as tool of Philosophy

1. Logic: as tool of Philosophy • Science of correct reasoning • Nature of man: correct thinking • To examine our ability to adapt: • in difficult or controversial cases. • Organizing ideas/arguments: • expressing them with more accuracy • drawing legitimate conclusions.

2. FORMAL & MATERIAL LOGIC • FORMAL LOGIC • CORRECTNESS RATHER THAN THE TRUTH • Has to do with correctness or sequence or the following of rules. • Not on the material content of the argument. • To reason correctly is not necessarily the same as to reason truthfully.

3. E.g. Formal Logic: Practice makes perfect Nobody is perfect Why practice?

4. Pagsumama ka samatalino, tatalino ka rin! • Pagsumama ka saadik, magigingadik ka rin! • Try mo sumamasa AKIN… • Bakamaging AKIN ka rin!

5. MATERIAL LOGIC • Concerned with the truth • thought-contents is in correspondence with reality • Connection: mind & real order

6. E.g. Material Logic The human soul is endowed with intellect and will; But, what is endowed with intellect and will is spiritual; Ergo, the human soul is spiritual.

7. Potential recruits of Mass Media Industry are students who completed their course in Communication. • I’ve successfully completed my course in Communication last March of 2010. • I am therefore qualified to be a recruit of the Mass Media Industry.

8. Arguments • Nature of an argument • Argument is an inferential thinking that is composed of conclusion and premise(assertion/statement) from which the conclusion is inferred. • Inferential: the process of reasoning from a premise to a conclusion; in which the conclusion is drawn from evidential reasoning.

9. E.g. • Premise 1: anything that moves is moved by another; • Premise 2: but, the ball moves • Conclusion: therefore, the ball is moved by another.

10. INFERENTIAL? PREMISES WHAT IS CLAIMED TO FOLLOW FROM THE EVIDENCE CLAIMED EVIDENCE CONCLUSION

11. VALID & INVALID ARGUMENTS • Valid: (T-T) INFERENTIAL • The conclusion is true because of the true premises. • It is impossible that the premises of an argument are true and the conclusion false

12. VALID ARGUMENTS E.g. 1.  All chickboys have multiple partners/girlfriends.  2.  Ysmael & Iggy Boy have 10 girlfriends each at the same time.  __________________________ 3.  Therefore, Ysmael & Iggy Boy are both chickboys.

13. VALID ARGUMENTS 1.  All people who are born in the United States are U.S. citizens.  2.  Tutoy was born in the United States.  ____________________ 3.  Therefore, Tutoy is a U.S. citizen. 

14. VALID ARGUMENTS 1.  All mammals have kidneys. 2.  Plants do not have kidneys. ____________________ 3.  Therefore, plants are not mammals. 

15. INVALID ARGUMENTS (PRESUMPTUOUS) • T-F • The premises are true and the conclusion is false. • fallacy of affirming the consequent. • “Inductive: assuming” • “not necessarily… probably!” • (+) If it rains, then the ground gets wet. • (+) But, the ground is wet; • (-) Therefore, it rained.

16. INVALID ARGUMENTS 1.  If Arn-Arn is in Hollywood, then he is in California. 2.  Arn-Arn is in California. ______________________ 3. Therefore, Arn-Arn is in Hollywood. 

17. INVALID ARGUMENTS 1.  Horses are not reptiles. 2.  Mr. Diego is not a reptile. _________________ 3.  Therefore, Mr. Diego is a horse. 

18. “masarapmagmahal, • nagmamahalako, samakatuwid… • masarapako!” • God is love, • but love is blind. • Therefore, God is blind!”

19. VALID YET ABSURD • F-F • The premises are false (NOT MATERIAL) and it follows that the conclusion is false(NOT MATERIAL!) • It is valid because: the way in which the premises and conclusion are structured is “FORMALLY CORRECT!” • ALL TREES ARE WOMEN • BUT, ALL MEN ARE TREES • THEREFORE, ALL WOMEN ARE MEN

20. VALID: UNSOUND • One premise: false/true • Conclusion: true (accidental) • E.g. • (+) All dogs are animal; • (-) But, all cats are dogs; • (+) Therefore, all cats are animals.

21. VALID ARGUMENTS

22. INVALID ARGUMENTS